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)

2 files changed, 5 insertions, 5 deletions

diff --git a/modules/charset/charset_test.go b/modules/charset/charset_test.go
index cfd5fb5696..6dd13c039d 100644
--- a/modules/charset/charset_test.go
+++ b/modules/charset/charset_test.go
@@ -296,11 +296,11 @@ func TestDetectEncoding(t *testing.T) {
 }
 
 func stringMustStartWith(t *testing.T, expected, value string) {
-	assert.Equal(t, expected, string(value[:len(expected)]))
+	assert.Equal(t, expected, value[:len(expected)])
 }
 
 func stringMustEndWith(t *testing.T, expected, value string) {
-	assert.Equal(t, expected, string(value[len(value)-len(expected):]))
+	assert.Equal(t, expected, value[len(value)-len(expected):])
 }
 
 func bytesMustStartWith(t *testing.T, expected, value []byte) {
diff --git a/modules/charset/escape.go b/modules/charset/escape.go
index 20a4bb2a10..9c1baafba3 100644
--- a/modules/charset/escape.go
+++ b/modules/charset/escape.go
@@ -222,15 +222,15 @@ readingloop:
 		return
 	}
 	escaped.HasError = true
-	return
+	return escaped, err
 }
 
 func writeBroken(output io.Writer, bs []byte) (err error) {
 	_, err = fmt.Fprintf(output, `<span class="broken-code-point">&lt;%X&gt;</span>`, bs)
-	return
+	return err
 }
 
 func writeEscaped(output io.Writer, r rune) (err error) {
 	_, err = fmt.Fprintf(output, `<span class="escaped-code-point" data-escaped="[U+%04X]"><span class="char">%c</span></span>`, r, r)
-	return
+	return err
 }