Tokenization for match-case

Originally from @SNvMK in https://github.com/microsoft/vscode/issues/120734

So, in python 3.10, there is match/case syntax. Currently, it is just white words(for monokai). I'd like if you add highlight for this. Thanks

a = 'world'
match a:
    case 'world':
        print('Hello!')
    case _:
        print('I dont know you!')

Currently the match and case are only tokenized as source.python.

首先定位此语法高亮器使用的 Python 标记化规则，并将 issue 中 match/case 示例的处理方式与现有关键字规则进行比较。完成的标准是：在受支持的编辑器中为 match 和 case 提供适当的语法高亮，同时不改变无关的 Python 高亮。