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/api/v1/repo/pull.go

@@ -1058,7 +1058,6 @@ func parseCompareInfo(ctx *context.APIContext, form api.CreatePullRequestOption)
 		isSameRepo = true
 		headUser = ctx.Repo.Owner
 		headBranch = headInfos[0]
-
 	} else if len(headInfos) == 2 {
 		headUser, err = user_model.GetUserByName(ctx, headInfos[0])
 		if err != nil {
@@ -1072,7 +1071,6 @@ func parseCompareInfo(ctx *context.APIContext, form api.CreatePullRequestOption)
 		headBranch = headInfos[1]
 		// The head repository can also point to the same repo
 		isSameRepo = ctx.Repo.Owner.ID == headUser.ID
-
 	} else {
 		ctx.NotFound()
 		return nil, nil, nil, nil, "", ""