Fix #643 - Add support for write-good for many languages

ale_linters/xhtml/write-good.vim

@@ -0,0 +1,9 @@
+" Author: Sumner Evans <sumner.evans98@gmail.com>
+" Description: write-good for XHTML files
+
+call ale#linter#Define('xhtml', {
+\   'name': 'write-good',
+\   'executable_callback': 'ale#handlers#writegood#GetExecutable',
+\   'command_callback': 'ale#handlers#writegood#GetCommand',
+\   'callback': 'ale#handlers#writegood#Handle',
+\})