ale#Escape function seems to prepend and append ' to the file name, which
are not present in the pydocstyle output. Having the parsing regexp match
the file name was overkill anyway, since there is an obvious 1:1
correspondence between the buffer number and the (potential) errors
reported by pydocstyle.
The linter can correctly parse pydocstyle output with any of the following
command-line options enabled: --explain, --source, --debug, and/or
--verbose