Invalid README

[Reububble]

https://github.com/microsoft/TypeScript-DOM-lib-generator/blob/main/inputfiles/idl/README.md

Seems to indicate that there is a "fetch" task, which unless I'm mistaken, was removed in #1349

[Bashamega]

Hello @Reububble,
This issue was solved in #1869