Update gitdiff.go

Author: wxiaoguang

services/gitdiff/gitdiff.go

@@ -412,7 +412,7 @@ func (hcd *HighlightCodeDiff) convertToPlaceholders(htmlCode string) string {
 			res.WriteRune(placeholder) // use the placeholder to replace the tag
 		} 
 		// else: unfortunately, all private use runes has been exhausted, no more placeholder could be used, no more converting
-		// usually, the exhausting won't occur in real cases, the used placeholders are not more than the CSS classes outputted by chroma.
+		// usually, the exhausting won't occur in real cases, the magnitude of used placeholders is not larger than that of the CSS classes outputted by chroma.
 	}
 	// write the remaining string
 	res.WriteString(htmlCode)