Enable more revive linter rules (#30608)

Noteable additions:

- `redefines-builtin-id` forbid variable names that shadow go builtins
- `empty-lines` remove unnecessary empty lines that `gofumpt` does not
remove for some reason
- `superfluous-else` eliminate more superfluous `else` branches

Rules are also sorted alphabetically and I cleaned up various parts of
`.golangci.yml`.

(cherry picked from commit 74f0c84fa4245a20ce6fb87dac1faf2aeeded2a2)

Conflicts:
	.golangci.yml
	apply the linter recommendations to Forgejo code as well

routers/web/repo/pull.go

@@ -670,7 +670,6 @@ func PrepareViewPullInfo(ctx *context.Context, issue *issues_model.Issue) *git.C
 	}
 
 	if pb != nil && pb.EnableStatusCheck {
-
 		var missingRequiredChecks []string
 		for _, requiredContext := range pb.StatusCheckContexts {
 			contextFound := false
@@ -873,7 +872,6 @@ func viewPullFiles(ctx *context.Context, specifiedStartCommit, specifiedEndCommi
 
 	// Validate the given commit sha to show (if any passed)
 	if willShowSpecifiedCommit || willShowSpecifiedCommitRange {
-
 		foundStartCommit := len(specifiedStartCommit) == 0
 		foundEndCommit := len(specifiedEndCommit) == 0
 
@@ -1185,7 +1183,6 @@ func UpdatePullRequest(ctx *context.Context) {
 			ctx.Flash.Error(flashError)
 			ctx.Redirect(issue.Link())
 			return
-
 		}
 		ctx.Flash.Error(err.Error())
 		ctx.Redirect(issue.Link())