docs: x/distribution spec (#8928)

* EndBlock => BeginBlock

* Add high-level algorithm

* Update documentation on params invariant

* Comment fix

* Update and extend BeginBlock documentation

* Update hooks documentation

* New intro to the concepts

* Update messages documentation

* Write in full sentences

Co-authored-by: Robert Zaremba <robert@zaremba.ch>

* spelling error

* change link

* slashing spec clarification

* Revert "slashing spec clarification"

This reverts commit b08b5a8533ca9d355a0afb0e58254b95487ce880.

* Update x/distribution/spec/04_messages.md

Co-authored-by: Robert Zaremba <robert@zaremba.ch>

* Update x/distribution/spec/03_begin_block.md

Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>

* update link to latest version

* Update x/distribution/spec/04_messages.md

Co-authored-by: Robert Zaremba <robert@zaremba.ch>

* clarify note on removed validator

* clarify validator removed hook

* clarify validator created hook

* clarify delegation modified/created hook

* clarify slash hook

* clarify possesive singular situation

* clarify hooks.go

* Move comment to clearer position

* Update x/distribution/spec/01_concepts.md

Co-authored-by: Barrie Byron <barrie.byron@tendermint.com>

* clarifications in concepts file

* Clarify introductory paragraphs

* communitytax => community_tax

* Apply suggestions from code review

Co-authored-by: Barrie Byron <barrie.byron@tendermint.com>
Co-authored-by: Robert Zaremba <robert@zaremba.ch>

* Update delegator rewards descirption

* Remove "this"

* Fix error in non-proposer validator rewards spec

* Clarify validator rewards high level description

* Update x/distribution/spec/04_messages.md

* Clarify what fees are

* Misc grammar and style fixes

* Apply suggestions from code review

Co-authored-by: Barrie Byron <barrie.byron@tendermint.com>

* Apply suggestions from code review

Co-authored-by: Barrie Byron <barrie.byron@tendermint.com>
Co-authored-by: Ethan Buchman <ethan@coinculture.info>

Co-authored-by: Jack Zampolin <jack.zampolin@gmail.com>
Co-authored-by: Marko <marbar3778@yahoo.com>
Co-authored-by: Robert Zaremba <robert@zaremba.ch>
Co-authored-by: Federico Kunze <31522760+fedekunze@users.noreply.github.com>
Co-authored-by: Barrie Byron <barrie.byron@tendermint.com>
Co-authored-by: Alessio Treglia <alessio@tendermint.com>
Co-authored-by: Ethan Buchman <ethan@coinculture.info>

x/slashing/spec/02_state.md

@@ -12,7 +12,7 @@ long as it contains precommits from +2/3 of total voting power.
 
 Proposers are incentivized to include precommits from all validators in the Tendermint `LastCommitInfo`
 by receiving additional fees proportional to the difference between the voting
-power included in the `LastCommitInfo` and +2/3 (see [fee distribution](https://github.com/cosmos/cosmos-sdk/blob/master/docs/spec/fee_distribution)).
+power included in the `LastCommitInfo` and +2/3 (see [fee distribution](x/distribution/spec/03_begin_block.md)).
 
 ```
 type LastCommitInfo struct {