vim-patch:9.1.0317: filetype: matplotlibrc files are not recognized

Problem:  filetype: matplotlibrc files are not recognized
Solution: Detect 'matplotlibrc' file as yaml filetype
          (Wu, Zhenyu)

See: https://matplotlib.org/stable/users/explain/customizing.html#the-matplotlibrc-file

closes: vim/vim#14501

55d4f3c006

Co-authored-by: Wu, Zhenyu <wuzhenyu@ustc.edu>

runtime/lua/vim/filetype.lua

@@ -1660,6 +1660,7 @@ local filename = {
   ['.clang-format'] = 'yaml',
   ['.clang-tidy'] = 'yaml',
   ['yarn.lock'] = 'yaml',
+  matplotlibrc = 'yaml',
   zathurarc = 'zathurarc',
   ['/etc/zprofile'] = 'zsh',
   ['.zlogin'] = 'zsh',

test/old/testdir/test_filetype.vim

@@ -837,7 +837,7 @@ func s:GetFilenameChecks() abort
     \ 'xsd': ['file.xsd'],
     \ 'xslt': ['file.xsl', 'file.xslt'],
     \ 'yacc': ['file.yy', 'file.yxx', 'file.y++'],
-    \ 'yaml': ['file.yaml', 'file.yml', 'file.eyaml', 'any/.bundle/config', '.clangd', '.clang-format', '.clang-tidy', 'file.mplstyle', 'yarn.lock'],
+    \ 'yaml': ['file.yaml', 'file.yml', 'file.eyaml', 'any/.bundle/config', '.clangd', '.clang-format', '.clang-tidy', 'file.mplstyle', 'matplotlibrc', 'yarn.lock'],
     \ 'yang': ['file.yang'],
     \ 'yuck': ['file.yuck'],
     \ 'z8a': ['file.z8a'],