patch 8.2.3469: some files with json syntax are not recognized

Problem:    Some files with json syntax are not recognized.
Solution:   Add a few file patterns. (Emiliano Ruiz Carletti, closes #8947)

runtime/filetype.vim

@@ -876,6 +876,9 @@ au BufNewFile,BufRead *.json-patch			setf json
 " Jupyter Notebook is also json
 au BufNewFile,BufRead *.ipynb				setf json
 
+" Other files that look like json
+au BufNewFile,BufRead .babelrc,.eslintrc,.prettierrc,.firebaserc  setf json
+
 " JSONC
 au BufNewFile,BufRead *.jsonc			setf jsonc