Cannot use `is`, `isnot` for variable name

[tyru]

trafficstars

let is = 42

vimlparser: unexpected token: is: line 75 col 5

let isnot = 42

vimlparser: unexpected token: isnot: line 75 col 5

[koron]

tokenizer が先に token として認識しちゃってそう。 https://github.com/vim-jp/vim-vimlparser/blob/4139d51700ed72702bd9f7352e5359ac0cf54c6c/autoload/vimlparser.vim#L3301-L3310