perf: apply perfpsrint linter (#33967) (#34632)

* perf: apply perfpsrint linter (#33967)

* perf: apply perfpsrint linter

* further simplifications

* improved TestParseHashtags coverage

* more simplifications

* simplify renderBlockHTML further

---------

Co-authored-by: Jesse Hallam <jesse@mattermost.com>

* Fixed a bad merge

---------

Co-authored-by: Catena cyber <35799796+catenacyber@users.noreply.github.com>
Co-authored-by: Jesse Hallam <jesse@mattermost.com>

server/public/shared/markdown/indented_code.go

@@ -19,11 +19,12 @@ type IndentedCode struct {
 	RawCode []IndentedCodeLine
 }
 
-func (b *IndentedCode) Code() (result string) {
+func (b *IndentedCode) Code() string {
+	var resultSb strings.Builder
 	for _, code := range b.RawCode {
-		result += strings.Repeat(" ", code.Indentation) + b.markdown[code.Range.Position:code.Range.End]
+		resultSb.WriteString(strings.Repeat(" ", code.Indentation) + b.markdown[code.Range.Position:code.Range.End])
 	}
-	return
+	return resultSb.String()
 }
 
 func (b *IndentedCode) Continuation(indentation int, r Range) *continuation {