Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

modules/git/batch_reader.go

@@ -176,12 +176,12 @@ func ReadBatchLine(rd *bufio.Reader) (sha []byte, typ string, size int64, err er
 	typ = typ[:idx]
 
 	size, err = strconv.ParseInt(sizeStr, 10, 64)
-	return
+	return sha, typ, size, err
 }
 
 // ReadTagObjectID reads a tag object ID hash from a cat-file --batch stream, throwing away the rest of the stream.
 func ReadTagObjectID(rd *bufio.Reader, size int64) (string, error) {
-	id := ""
+	var id string
 	var n int64
 headerLoop:
 	for {
@@ -216,7 +216,7 @@ headerLoop:
 
 // ReadTreeID reads a tree ID from a cat-file --batch stream, throwing away the rest of the stream.
 func ReadTreeID(rd *bufio.Reader, size int64) (string, error) {
-	id := ""
+	var id string
 	var n int64
 headerLoop:
 	for {
@@ -328,7 +328,7 @@ func ParseTreeLine(rd *bufio.Reader, modeBuf, fnameBuf, shaBuf []byte) (mode, fn
 	// Deal with the 20-byte SHA
 	idx = 0
 	for idx < 20 {
-		read := 0
+		var read int
 		read, err = rd.Read(shaBuf[idx:20])
 		n += read
 		if err != nil {
@@ -337,7 +337,7 @@ func ParseTreeLine(rd *bufio.Reader, modeBuf, fnameBuf, shaBuf []byte) (mode, fn
 		idx += read
 	}
 	sha = shaBuf
-	return
+	return mode, fname, sha, n, err
 }
 
 var callerPrefix string