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/contributors_graph.go

@@ -194,7 +194,6 @@ func getExtendedCommitStats(repo *git.Repository, revision string /*, limit int
 					Stats: &commitStats,
 				}
 				extendedCommitStats = append(extendedCommitStats, res)
-
 			}
 			_ = stdoutReader.Close()
 			return nil