fix: Python functions should be highlighted as functions (#4708)

Author: zardam

lib/ace/mode/_test/tokens_python.json

@@ -333,7 +333,7 @@
    "start",
   ["keyword","def"],
   ["text"," "],
-  ["identifier","to_lowercase"],
+  ["entity.name.function","to_lowercase"],
   ["paren.lparen","("],
   ["support.function","input"],
   ["paren.rparen",")"],

lib/ace/mode/python_highlight_rules.js

@@ -170,6 +170,9 @@ var PythonHighlightRules = function() {
             token: "paren.rparen",
             regex: "[\\]\\)\\}]"
         }, {
+            token: ["keyword", "text", "entity.name.function"],
+            regex: "(def|class)(\\s+)(\\w+)"
+         }, {
             token: "text",
             regex: "\\s+"
         }, {