Cannot have python keyword in route name

[jrozentur]

🐞 Describe the bug

This code is rejected with 'Incorrect route name':

@app_routes.get('/result/', name='check-for-result')
async def result(request):

This is because 'for' is a keyword, and the check rejects any keywords for some strange reason:
in https://github.com/aio-libs/aiohttp/blob/master/aiohttp/web_urldispatcher.py#L982

parts = self.NAME_SPLIT_RE.split(name)
for part in parts:
      if not part.isidentifier() or keyword.iskeyword(part):
           raise ValueError

I think the intention was to have:

if not (part.isidentifier() or keyword.iskeyword(part))

💡 To Reproduce

💡 Expected behavior

Should accept route names containing python keywords

📋 Logs/tracebacks

📋 Your version of the Python

$ python --version
Python 3.7.4

📋 Your version of the aiohttp/yarl/multidict distributions

$ python -m pip show aiohttp
Version: 3.6.2

$ python -m pip show multidict
Version: 4.7.5

$ python -m pip show yarl
Version: 1.3.0

📋 Additional context

[webknjaz]

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