Fix regex for 'def' and 'async def'

Author: 1st1

grammars/MagicPython.cson

@@ -1058,7 +1058,7 @@ repository:
     begin: '''
       (?x)
         \\s*
-        (?:(async) \\s+)? (def)\\s+
+        (?:\\b(async) \\s+)? \\b(def)\\s+
           (?=
             [[:alpha:]_][[:word:]]* \\s* \\(
           )

grammars/MagicPython.tmLanguage

@@ -1706,7 +1706,7 @@ it's not tokenized as ellipsis.
         <key>begin</key>
         <string>(?x)
   \s*
-  (?:(async) \s+)? (def)\s+
+  (?:\b(async) \s+)? \b(def)\s+
     (?=
       [[:alpha:]_][[:word:]]* \s* \(
     )

grammars/src/MagicPython.syntax.yaml

@@ -730,7 +730,7 @@ repository:
     begin: |
       (?x)
         \s*
-        (?:(async) \s+)? (def)\s+
+        (?:\b(async) \s+)? \b(def)\s+
           (?=
             [[:alpha:]_][[:word:]]* \s* \(
           )

test/functions/async3.py

@@ -0,0 +1,14 @@
+casync def foo(): pass
+
+
+
+casync        : source.python
+              : meta.function.python, source.python
+def           : meta.function.python, source.python, storage.type.function.python
+              : meta.function.python, source.python
+foo           : entity.name.function.python, meta.function.python, source.python
+(             : meta.function.parameters.python, meta.function.python, punctuation.definition.parameters.begin.python, source.python
+)             : meta.function.parameters.python, meta.function.python, punctuation.definition.parameters.end.python, source.python
+:             : meta.function.python, punctuation.section.function.begin.python, source.python
+              : source.python
+pass          : keyword.control.flow.python, source.python

test/functions/decl9.py

@@ -0,0 +1,10 @@
+cdef foo(): pass
+
+
+
+cdef          : source.python
+foo           : meta.function-call.generic.python, meta.function-call.python, source.python
+(             : meta.function-call.python, punctuation.definition.arguments.begin.python, source.python
+)             : meta.function-call.python, punctuation.definition.arguments.end.python, source.python
+:             : source.python
+pass          : keyword.control.flow.python, source.python