Fix mypy error parsing when column numbers are included.

ale_linters/python/mypy.vim

@@ -16,6 +16,8 @@ function! g:ale_linters#python#mypy#GetCommand(buffer) abort
     \   . g:ale_python_mypy_options
 endfunction
 
+let s:path_pattern = '[a-zA-Z]\?\\\?:\?[[:alnum:]/\.\-_]\+'
+
 function! g:ale_linters#python#mypy#Handle(buffer, lines) abort
     " Look for lines like the following:
     "
@@ -24,7 +26,7 @@ function! g:ale_linters#python#mypy#Handle(buffer, lines) abort
     " Lines like these should be ignored below:
     "
     " file.py:4: note: (Stub files are from https://github.com/python/typeshed)
-    let l:pattern = '^.\+:\(\d\+\):\?\(\d\+\)\?: \([^:]\+\): \(.\+\)$'
+    let l:pattern = '^' . s:path_pattern . ':\(\d\+\):\?\(\d\+\)\?: \([^:]\+\): \(.\+\)$'
     let l:output = []
 
     for l:line in a:lines

test/test_mypy_handler.vader

@@ -12,10 +12,20 @@ Execute(The mypy handler should parse lines correctly):
   \     'type': 'E',
   \     'nr': -1,
   \   },
+  \   {
+  \     'bufnr': 347,
+  \     'lnum': 40,
+  \     'vcol': 0,
+  \     'col': 5,
+  \     'text': "Some other problem",
+  \     'type': 'E',
+  \     'nr': -1,
+  \   },
   \ ],
   \ ale_linters#python#mypy#Handle(347, [
   \   "file.py:4: error: No library stub file for module 'django.db'",
   \   'file.py:4: note: (Stub files are from https://github.com/python/typeshed)',
+  \   "file.py:40:5: error: Some other problem",
   \ ])
 
 After: