Fix PHP lint generic error without line number

This makes php output more specific error messages. The format is the normal one ALE expects, but on some systems ALE does not work with PHP unless the display_errors=1 option is used. Without that option php will only output a generic message without a line number like "Errors parsing index.php"

ale_linters/php/php.vim

@@ -34,6 +34,6 @@ call ale#linter#Define('php', {
 \   'name': 'php',
 \   'executable': 'php',
 \   'output_stream': 'both',
-\   'command': 'php -l --',
+\   'command': 'php -l -d display_errors=1 --',
 \   'callback': 'ale_linters#php#php#Handle',
 \})