Problem: filetype: some requirements files are not recognized
Solution: Detect '*-requirements.txt', 'constraints.txt',
'requirements.in', 'requirements/*.txt' and 'requires/*.txt'
as requirements filetype, include pip compiler, include
requirements filetype and syntax plugin
(Wu, Zhenyu, @raimon49)
closes: vim/vim#14379f9f5424d3e
Co-authored-by: Wu, Zhenyu <wuzhenyu@ustc.edu>
Co-authored-by: raimon <raimon49@hotmail.com>
