vim-patch:9.1.1396: 'grepformat' is a global option (#34060)

Problem:  The 'grepformat' option is global option, but it would be
          useful to have it buffer-local, similar to 'errorformat' and
          other quickfix related options (Dani Dickstein)
Solution: Add the necessary code to support global-local 'grepformat',
          allowing different buffers to parse different grep output
          formats (glepnir)

fixes: vim/vim#17316
closes: vim/vim#17315

7b9eb6389d

Co-authored-by: glepnir <glephunter@gmail.com>

src/nvim/options.lua

@@ -3694,7 +3694,7 @@ local options = {
       ]=],
       full_name = 'grepformat',
       list = 'onecomma',
-      scope = { 'global' },
+      scope = { 'global', 'buf' },
       short_desc = N_("format of 'grepprg' output"),
       type = 'string',
       varname = 'p_gefm',