VSCode Code Spell Checker extension - include .todo files

I'm using vscode extension for spell checking:

https://marketplace.visualstudio.com/items?itemName=streetsidesoftware.code-spell-checker

The problem is - I can't include ".todo" files type. (my .todo files are not in any markup language. They are just "plain text").

I tried(none works for me):

• "cSpell.files": ["**/**.todo"] (also turns off all existing files check)
• "cSpell.enableFiletypes": [ "*" ] to inclue all fiels types

I notice there is a languages list, but didn't find way to add new one.

I found out, that by default spell check extension ignore all files from .gitignore.

In my case solution was to add following Modifications in my vscode user settings:

"cSpell.enableFiletypes": [
  "todo" // enable .todo files checking
],
"cSpell.useGitignore": false, // disable ignoring files from .gitignore

Thanks to everyone who tried to help me!