patch 8.2.3603: fish filetype not recognized

Problem:    Fish filetype not recognized.
Solution:   Add a file pattern and match script line. (Doug Kearns)

runtime/filetype.vim

@@ -617,6 +617,9 @@ autocmd BufRead,BufNewFile *.fnl		setf fennel
 " Fetchmail RC file
 au BufNewFile,BufRead .fetchmailrc		setf fetchmail
 
+" Fish shell
+au BufNewFile,BufRead *.fish			setf fish
+
 " FlexWiki - disabled, because it has side effects when a .wiki file
 " is not actually FlexWiki
 "au BufNewFile,BufRead *.wiki			setf flexwiki

runtime/scripts.vim

@@ -194,6 +194,10 @@ if s:line1 =~# "^#!"
   elseif s:name =~# 'rsc\>'
     set ft=routeros
 
+    " Fish shell
+  elseif s:name =~# 'fish\>'
+    set ft=fish
+
   endif
   unlet s:name