Return a list instead of bare path string.

GitHub-Issue: 10
#10

This is a simple mistake. This function requires a string list, this
pattern assigns just a string to the variable.
Since a character string is a type of sequence, the append function
treats it as a vector of char(int) instead of type error.

This issue was reported by @kwvanderlinde, thanks!

Author: zonuexe

phpstan.el

@@ -224,7 +224,8 @@ it returns the value of `SOURCE' as it is."
           "phpstan/phpstan"))
    ((and (consp phpstan-executable)
          (eq 'root (car phpstan-executable)))
-    (expand-file-name (cdr phpstan-executable) (php-project-get-root-dir)))
+    (list
+     (expand-file-name (cdr phpstan-executable) (php-project-get-root-dir))))
    ((and (stringp phpstan-executable) (file-exists-p phpstan-executable))
     (list phpstan-executable))
    ((and phpstan-flycheck-auto-set-executable