patch 9.1.0965: filetype: sh filetype set when detecting the use of bash

Problem:  filetype: sh filetype set when detecting the use of bash
Solution: when bash is detected, use 'bash' filetype instead
          (Luca Saccarola)

closes: #16309

Signed-off-by: Luca Saccarola <github.e41mv@aleeas.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/autoload/dist/ft.vim

@@ -896,6 +896,7 @@ export def SetFileTypeSH(name: string, setft = true): string
     if exists("b:is_sh")
       unlet b:is_sh
     endif
+    return SetFileTypeShell("bash", setft)
   elseif name =~ '\<sh\>' || name =~ '\<dash\>'
     # Ubuntu links "sh" to "dash", thus it is expected to work the same way
     b:is_sh = 1