Fix PHP column matching for unexpected single quotes (#370)

* PHP: Fix column matching for unexpected single quotes

Unexpected single quotes resulted in an empty match, because PHP
surrounds the errors with quotes, and we check for the next quote to be
the ending delimiter.

For example: an unexpected string 'foo' would be presented as
`unexpected ''foo''`, and then the match would be `''`. The inner part
of that match is an empty string.

This adds a check for the keyword "expecting". Any quote after
"expecting" won't be matched, so we can use greedy matching instead of
non-greedy.

* PHP: Use "very magic"

The pattern started to get unreadable

Also replaced non-greedy matching (`\{-}`) by greedy matching, because
we don't need to match non-greedily anymore and it reads a little nicer.

* PHP: Add tests for column matches

And with that, also a test for unexpected single quotes.

ale_linters/php/php.vim

@@ -5,7 +5,7 @@ function! ale_linters#php#php#Handle(buffer, lines) abort
     " Matches patterns like the following:
     "
     " PHP Parse error:  syntax error, unexpected ';', expecting ']' in - on line 15
-    let l:pattern = 'Parse error:\s\+\(.\{-}unexpected ''\(.\{-}\)''.\{-}\|.*\) in - on line \(\d\+\)'
+    let l:pattern = '\vParse error:\s+(.+unexpected ''(.+)%(expecting.+)@<!''.*|.+) in - on line (\d+)'
 
     let l:output = []