Support variable annotation when variable start by a keyword

Support case when the variable name start by a keyword, eg:
```
class Test:
    formula: str = None
```

Author: rach

pycodestyle.py

@@ -124,7 +124,7 @@
 STARTSWITH_DEF_REGEX = re.compile(r'^(async\s+def|def)')
 STARTSWITH_TOP_LEVEL_REGEX = re.compile(r'^(async\s+def\s+|def\s+|class\s+|@)')
 STARTSWITH_INDENT_STATEMENT_REGEX = re.compile(
-    r'^\s*({0})'.format('|'.join(s.replace(' ', '\s+') for s in (
+    r'^\s*({0})\s'.format('|'.join(s.replace(' ', '\s+') for s in (
         'def', 'async def',
         'for', 'async for',
         'if', 'elif', 'else',