runtime(mysql): include mysql ftplugin file

This one just sources from the SQL ftplugin. Without this, *.mysql
files don't inherit the common SQL settings.

closes: #15166

Signed-off-by: Riley Bruins <ribru17@hotmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/mysql.vim b/runtime/ftplugin/mysql.vim
new file mode 100644
index 0000000..cbbd0eb
--- /dev/null
+++ b/runtime/ftplugin/mysql.vim
@@ -0,0 +1 @@
+runtime ftplugin/sql.vim