chore(upgrade): cleaning (#10413)

## Description

cosmetic changes spotted when reading docs and code.

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

types/module/module.go

@@ -415,32 +415,25 @@ func (m Manager) RunMigrations(ctx sdk.Context, cfg Configurator, fromVM Version
 		fromVersion, exists := fromVM[moduleName]
 		toVersion := module.ConsensusVersion()
 
-		// Only run migrations when the module exists in the fromVM.
-		// Run InitGenesis otherwise.
+		// We run migration if the module is specified in `fromVM`.
+		// Otherwise we run InitGenesis.
 		//
-		// the module won't exist in the fromVM in two cases:
+		// The module won't exist in the fromVM in two cases:
 		// 1. A new module is added. In this case we run InitGenesis with an
 		// empty genesis state.
-		// 2. An existing chain is upgrading to v043 for the first time. In this case,
-		// all modules have yet to be added to x/upgrade's VersionMap store.
+		// 2. An existing chain is upgrading from version < 0.43 to v0.43+ for the first time.
+		// In this case, all modules have yet to be added to x/upgrade's VersionMap store.
 		if exists {
 			err := c.runModuleMigrations(ctx, moduleName, fromVersion, toVersion)
 			if err != nil {
 				return nil, err
 			}
 		} else {
-			cfgtor, ok := cfg.(configurator)
-			if !ok {
-				// Currently, the only implementator of Configurator (the interface)
-				// is configurator (the struct).
-				return nil, sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "expected %T, got %T", configurator{}, cfg)
-			}
-
-			moduleValUpdates := module.InitGenesis(ctx, cfgtor.cdc, module.DefaultGenesis(cfgtor.cdc))
+			moduleValUpdates := module.InitGenesis(ctx, c.cdc, module.DefaultGenesis(c.cdc))
 			// The module manager assumes only one module will update the
-			// validator set, and that it will not be by a new module.
+			// validator set, and it can't be a new module.
 			if len(moduleValUpdates) > 0 {
-				return nil, sdkerrors.Wrapf(sdkerrors.ErrLogic, "validator InitGenesis updates already set by a previous module")
+				return nil, sdkerrors.Wrapf(sdkerrors.ErrLogic, "validator InitGenesis update is already set by another module")
 			}
 		}