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

services/repository/files/update.go

@@ -208,7 +208,6 @@ func ChangeRepoFiles(ctx context.Context, repo *repo_model.Repository, doer *use
 				return nil, fmt.Errorf("ConvertToSHA1: Invalid last commit ID: %w", err)
 			}
 			opts.LastCommitID = lastCommitID.String()
-
 		}
 
 		for _, file := range opts.Files {
@@ -360,7 +359,6 @@ func handleCheckErrors(file *ChangeRepoFile, commit *git.Commit, opts *ChangeRep
 					Path: file.Options.treePath,
 				}
 			}
-
 		}
 	}