Update runtime files

runtime/ftplugin/pbtxt.vim

@@ -0,0 +1,21 @@
+" Vim filetype plugin file
+" Language:             Protobuf Text Format
+" Maintainer:           Lakshay Garg <lakshayg@outlook.in>
+" Last Change:          2020 Nov 17
+" Homepage:             https://github.com/lakshayg/vim-pbtxt
+
+if exists("b:did_ftplugin")
+  finish
+endif
+
+let b:did_ftplugin = 1
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+setlocal commentstring=#\ %s
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+" vim: nowrap sw=2 sts=2 ts=8 noet