build: upgrade to go 1.19 (#25726)

This changes the CI / release builds to use the latest Go version. It also
upgrades golangci-lint to a newer version compatible with Go 1.19.

In Go 1.19, godoc has gained official support for links and lists. The
syntax for code blocks in doc comments has changed and now requires a
leading tab character. gofmt adapts comments to the new syntax
automatically, so there are a lot of comment re-formatting changes in this
PR. We need to apply the new format in order to pass the CI lint stage with
Go 1.19.

With the linter upgrade, I have decided to disable 'gosec' - it produces
too many false-positive warnings. The 'deadcode' and 'varcheck' linters
have also been removed because golangci-lint warns about them being
unmaintained. 'unused' provides similar coverage and we already have it
enabled, so we don't lose much with this change.

les/downloader/downloader.go

@@ -693,9 +693,11 @@ func (d *Downloader) fetchHead(p *peerConnection) (head *types.Header, pivot *ty
 // calculateRequestSpan calculates what headers to request from a peer when trying to determine the
 // common ancestor.
 // It returns parameters to be used for peer.RequestHeadersByNumber:
-//  from - starting block number
-//  count - number of headers to request
-//  skip - number of headers to skip
+//
+//	from  - starting block number
+//	count - number of headers to request
+//	skip  - number of headers to skip
+//
 // and also returns 'max', the last block which is expected to be returned by the remote peers,
 // given the (from,count,skip)
 func calculateRequestSpan(remoteHeight, localHeight uint64) (int64, int, int, uint64) {
@@ -1310,22 +1312,22 @@ func (d *Downloader) fetchReceipts(from uint64) error {
 // various callbacks to handle the slight differences between processing them.
 //
 // The instrumentation parameters:
-//  - errCancel:   error type to return if the fetch operation is cancelled (mostly makes logging nicer)
-//  - deliveryCh:  channel from which to retrieve downloaded data packets (merged from all concurrent peers)
-//  - deliver:     processing callback to deliver data packets into type specific download queues (usually within `queue`)
-//  - wakeCh:      notification channel for waking the fetcher when new tasks are available (or sync completed)
-//  - expire:      task callback method to abort requests that took too long and return the faulty peers (traffic shaping)
-//  - pending:     task callback for the number of requests still needing download (detect completion/non-completability)
-//  - inFlight:    task callback for the number of in-progress requests (wait for all active downloads to finish)
-//  - throttle:    task callback to check if the processing queue is full and activate throttling (bound memory use)
-//  - reserve:     task callback to reserve new download tasks to a particular peer (also signals partial completions)
-//  - fetchHook:   tester callback to notify of new tasks being initiated (allows testing the scheduling logic)
-//  - fetch:       network callback to actually send a particular download request to a physical remote peer
-//  - cancel:      task callback to abort an in-flight download request and allow rescheduling it (in case of lost peer)
-//  - capacity:    network callback to retrieve the estimated type-specific bandwidth capacity of a peer (traffic shaping)
-//  - idle:        network callback to retrieve the currently (type specific) idle peers that can be assigned tasks
-//  - setIdle:     network callback to set a peer back to idle and update its estimated capacity (traffic shaping)
-//  - kind:        textual label of the type being downloaded to display in log messages
+//   - errCancel:   error type to return if the fetch operation is cancelled (mostly makes logging nicer)
+//   - deliveryCh:  channel from which to retrieve downloaded data packets (merged from all concurrent peers)
+//   - deliver:     processing callback to deliver data packets into type specific download queues (usually within `queue`)
+//   - wakeCh:      notification channel for waking the fetcher when new tasks are available (or sync completed)
+//   - expire:      task callback method to abort requests that took too long and return the faulty peers (traffic shaping)
+//   - pending:     task callback for the number of requests still needing download (detect completion/non-completability)
+//   - inFlight:    task callback for the number of in-progress requests (wait for all active downloads to finish)
+//   - throttle:    task callback to check if the processing queue is full and activate throttling (bound memory use)
+//   - reserve:     task callback to reserve new download tasks to a particular peer (also signals partial completions)
+//   - fetchHook:   tester callback to notify of new tasks being initiated (allows testing the scheduling logic)
+//   - fetch:       network callback to actually send a particular download request to a physical remote peer
+//   - cancel:      task callback to abort an in-flight download request and allow rescheduling it (in case of lost peer)
+//   - capacity:    network callback to retrieve the estimated type-specific bandwidth capacity of a peer (traffic shaping)
+//   - idle:        network callback to retrieve the currently (type specific) idle peers that can be assigned tasks
+//   - setIdle:     network callback to set a peer back to idle and update its estimated capacity (traffic shaping)
+//   - kind:        textual label of the type being downloaded to display in log messages
 func (d *Downloader) fetchParts(deliveryCh chan dataPack, deliver func(dataPack) (int, error), wakeCh chan bool,
 	expire func() map[string]int, pending func() int, inFlight func() bool, reserve func(*peerConnection, int) (*fetchRequest, bool, bool),
 	fetchHook func([]*types.Header), fetch func(*peerConnection, *fetchRequest) error, cancel func(*fetchRequest), capacity func(*peerConnection) int,

les/downloader/queue.go

@@ -477,9 +477,10 @@ func (q *queue) ReserveReceipts(p *peerConnection, count int) (*fetchRequest, bo
 // to access the queue, so they already need a lock anyway.
 //
 // Returns:
-//   item     - the fetchRequest
-//   progress - whether any progress was made
-//   throttle - if the caller should throttle for a while
+//
+//	item     - the fetchRequest
+//	progress - whether any progress was made
+//	throttle - if the caller should throttle for a while
 func (q *queue) reserveHeaders(p *peerConnection, count int, taskPool map[common.Hash]*types.Header, taskQueue *prque.Prque,
 	pendPool map[string]*fetchRequest, kind uint) (*fetchRequest, bool, bool) {
 	// Short circuit if the pool has been depleted, or if the peer's already

les/downloader/resultstore.go

@@ -71,10 +71,11 @@ func (r *resultStore) SetThrottleThreshold(threshold uint64) uint64 {
 // wants to reserve headers for fetching.
 //
 // It returns the following:
-//   stale     - if true, this item is already passed, and should not be requested again
-//   throttled - if true, the store is at capacity, this particular header is not prio now
-//   item      - the result to store data into
-//   err       - any error that occurred
+//
+//	stale     - if true, this item is already passed, and should not be requested again
+//	throttled - if true, the store is at capacity, this particular header is not prio now
+//	item      - the result to store data into
+//	err       - any error that occurred
 func (r *resultStore) AddFetch(header *types.Header, fastSync bool) (stale, throttled bool, item *fetchResult, err error) {
 	r.lock.Lock()
 	defer r.lock.Unlock()