Update runtime files.

runtime/ftplugin/bash.vim

@@ -0,0 +1,31 @@
+" Vim filetype plugin file
+" Language:	bash
+" Maintainer:	Bram Moolenaar
+" Last Changed: 2019 Jan 12
+"
+" This is not a real filetype plugin.  It allows for someone to set 'filetype'
+" to "bash" in the modeline, and gets the effect of filetype "sh" with
+" b:is_bash set.  Idea from Mahmode Al-Qudsi.
+
+if exists("b:did_ftplugin")
+  finish
+endif
+
+let b:is_bash = 1
+if exists("b:is_sh")
+  unlet b:is_sh
+endif
+if exists("b:is_kornshell")
+  unlet b:is_kornshell
+endif
+
+" Setting 'filetype' here directly won't work, since we are being invoked
+" through an autocommand.  Do it later, on the BufWinEnter event.
+augroup bash_filetype
+  au BufWinEnter * call SetBashFt()
+augroup END
+
+func SetBashFt()
+  au! bash_filetype
+  set ft=sh
+endfunc