vim-patch:9.1.0636: filetype: ziggy files are not recognized

Problem:  filetype: ziggy files are not recognized
Solution: detect '*.ziggy' files as ziggy filetype,
          detect '*.ziggy-schema' files as ziggy-schema filetype
          (EliSauder)

References: https://ziggy-lang.io/

fixes: vim/vim#15355
closes: vim/vim#15367

https://github.com/vim/vim/commit/f4572cee35a6c224985e71116e676ab711c09af3

Co-authored-by: EliSauder <24995216+EliSauder@users.noreply.github.com>

runtime/lua/vim/filetype.lua

@@ -1246,6 +1246,8 @@ local extension = {
   z8a = 'z8a',
   zig = 'zig',
   zon = 'zig',
+  ziggy = 'ziggy',
+  ['ziggy-schema'] = 'ziggy_schema',
   zu = 'zimbu',
   zut = 'zimbutempl',
   zs = 'zserio',

test/old/testdir/test_filetype.vim

@@ -862,6 +862,8 @@ func s:GetFilenameChecks() abort
     \ 'z8a': ['file.z8a'],
     \ 'zathurarc': ['zathurarc'],
     \ 'zig': ['file.zig', 'build.zig.zon'],
+    \ 'ziggy': ['file.ziggy'],
+    \ 'ziggy_schema': ['file.ziggy-schema'],
     \ 'zimbu': ['file.zu'],
     \ 'zimbutempl': ['file.zut'],
     \ 'zserio': ['file.zs'],