Add support for Fountain with proselint.

ale_linters/fountain/proselint.vim

@@ -0,0 +1,9 @@
+" Author: Jansen Mitchell https://github.com/JansenMitchell
+" Description: proselint for Fountain files
+
+call ale#linter#Define('fountain', {
+\	'name': 'proselint',
+\	'executable': 'proselint',
+\	'command': 'proselint %t',
+\	'callback': 'ale#handlers#unix#HandleAsWarning',
+\})