Add pythonNone to pythonExpression

Closes vim-python#54

Author: cdonovick

syntax/python.vim

@@ -92,7 +92,7 @@ else
   syn match   pythonStatement   '\<async\s\+def\>' nextgroup=pythonFunction skipwhite
   syn match   pythonStatement   '\<async\s\+with\>'
   syn match   pythonStatement   '\<async\s\+for\>'
-  syn cluster pythonExpression contains=pythonStatement,pythonRepeat,pythonConditional,pythonOperator,pythonNumber,pythonHexNumber,pythonOctNumber,pythonBinNumber,pythonFloat,pythonString,pythonBytes,pythonBoolean,pythonBuiltinObj,pythonBuiltinFunc
+  syn cluster pythonExpression contains=pythonStatement,pythonRepeat,pythonConditional,pythonOperator,pythonNumber,pythonHexNumber,pythonOctNumber,pythonBinNumber,pythonFloat,pythonString,pythonBytes,pythonBoolean,pythonNone,pythonBuiltinObj,pythonBuiltinFunc
 endif
 
 

tests/test.py

@@ -233,7 +233,7 @@ async def Test
 b"${test} ${test ${test}aname $$$ $test+nope"
 
 f"{var}...{arr[123]} normal {var['{'] // 0xff} \"xzcb\" 'xzcb' {var['}'] + 1} text"
-f"{expr1 if True or False else expr2} wow {','.join(c.lower() for c in 'asdf')}"
+f"{expr1 if True or False else expr2} {None} wow {','.join(c.lower() for c in 'asdf')}"
 f"hello {expr:.2f} yes {(lambda: 0b1)():#03x} lol {var!r}"
 f'brackets: {{ 1 + 2 }} and {{{{ 3 + 4 }}}}'
 fr'this {that}'