json: Generalize "keywordSuggestion" for general name suggestions

keywordSuggestion is now a wrapper around nameSuggestion with a predefined
list of names.

zcl/json/didyoumean.go

@@ -10,10 +10,23 @@ var keywords = []string{"false", "true", "null"}
 // given string and returns it if found. If no keyword is close enough, returns
 // the empty string.
 func keywordSuggestion(given string) string {
-	for _, kw := range keywords {
+	return nameSuggestion(given, keywords)
-		dist := levenshtein.Distance(given, kw, nil)
+}
+
+// nameSuggestion tries to find a name from the given slice of suggested names
+// that is close to the given name and returns it if found. If no suggestion
+// is close enough, returns the empty string.
+//
+// The suggestions are tried in order, so earlier suggestions take precedence
+// if the given string is similar to two or more suggestions.
+//
+// This function is intended to be used with a relatively-small number of
+// suggestions. It's not optimized for hundreds or thousands of them.
+func nameSuggestion(given string, suggestions []string) string {
+	for _, suggestion := range suggestions {
+		dist := levenshtein.Distance(given, suggestion, nil)
 		if dist < 3 { // threshold determined experimentally
-			return kw
+			return suggestion
 		}
 	}
 	return ""