Adds PHPActor Linter (LSP) (#3975)

* Adds phpactor lsp linter

* Fixes missing comma

* Adds tests for phpactor lsp linter

* Adds note that this part is not my own work

* Removes unused variable

* Adds phpactor to supported tools list

* Fixes doc sorting

* Wraps phpactor in code tags

doc/ale-supported-languages-and-tools.txt

@@ -382,6 +382,7 @@ Notes:
   * `phan`
   * `php -l`
   * `php-cs-fixer`
+  * `phpactor`
   * `phpcbf`
   * `phpcs`
   * `phpmd`