Update runtime files.

runtime/ftplugin/wast.vim

@@ -0,0 +1,17 @@
+" Vim filetype plugin file
+" Language:     WebAssembly
+" Maintainer:   rhysd <lin90162@yahoo.co.jp>
+" Last Change:  Jul 29, 2018
+" For bugs, patches and license go to https://github.com/rhysd/vim-wasm
+
+if exists("b:did_ftplugin")
+    finish
+endif
+let b:did_ftplugin = 1
+
+setlocal comments=s:(;,e:;),:;;
+setlocal commentstring=(;%s;)
+setlocal formatoptions-=t
+setlocal iskeyword+=$,.,/
+
+let b:undo_ftplugin = "setlocal comments< commentstring< formatoptions< iskeyword<"