Remove unused internal or unexported functions (#3481)

pkg/highlight/highlighter.go

@@ -51,19 +51,6 @@ func runePos(p int, str []byte) int {
 	return CharacterCount(str[:p])
 }
 
-func combineLineMatch(src, dst LineMatch) LineMatch {
-	for k, v := range src {
-		if g, ok := dst[k]; ok {
-			if g == 0 {
-				dst[k] = v
-			}
-		} else {
-			dst[k] = v
-		}
-	}
-	return dst
-}
-
 // A State represents the region at the end of a line
 type State *region