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`.

modules/git/batch_reader.go

@@ -307,10 +307,10 @@ func ParseTreeLine(objectFormat ObjectFormat, rd *bufio.Reader, modeBuf, fnameBu
 
 	// Deal with the binary hash
 	idx = 0
-	len := objectFormat.FullLength() / 2
-	for idx < len {
+	length := objectFormat.FullLength() / 2
+	for idx < length {
 		var read int
-		read, err = rd.Read(shaBuf[idx:len])
+		read, err = rd.Read(shaBuf[idx:length])
 		n += read
 		if err != nil {
 			return mode, fname, sha, n, err

modules/git/commit_reader.go

@@ -49,9 +49,8 @@ readLoop:
 			if len(line) > 0 && line[0] == ' ' {
 				_, _ = signatureSB.Write(line[1:])
 				continue
-			} else {
-				pgpsig = false
 			}
+			pgpsig = false
 		}
 
 		if !message {

modules/git/pipeline/lfs_nogogit.go

@@ -232,7 +232,6 @@ func FindLFSFile(repo *git.Repository, objectID git.ObjectID) ([]*LFSResult, err
 				errChan <- err
 				break
 			}
-
 		}
 	}()
 

modules/git/repo_commit.go

@@ -251,18 +251,18 @@ func (repo *Repository) CommitsByFileAndRange(opts CommitsByFileAndRangeOptions)
 		return nil, err
 	}
 
-	len := objectFormat.FullLength()
+	length := objectFormat.FullLength()
 	commits := []*Commit{}
-	shaline := make([]byte, len+1)
+	shaline := make([]byte, length+1)
 	for {
 		n, err := io.ReadFull(stdoutReader, shaline)
-		if err != nil || n < len {
+		if err != nil || n < length {
 			if err == io.EOF {
 				err = nil
 			}
 			return commits, err
 		}
-		objectID, err := NewIDFromString(string(shaline[0:len]))
+		objectID, err := NewIDFromString(string(shaline[0:length]))
 		if err != nil {
 			return nil, err
 		}

modules/git/submodule.go

@@ -64,7 +64,6 @@ func getRefURL(refURL, urlPrefix, repoFullName, sshDomain string) string {
 		// ex: git@try.gitea.io:go-gitea/gitea
 		match := scpSyntax.FindAllStringSubmatch(refURI, -1)
 		if len(match) > 0 {
-
 			m := match[0]
 			refHostname := m[2]
 			pth := m[3]