@babel/parser(ts): TSTypePredicate should include asserts into its range

[armano2]

Bug Report

• I would like to work on a fix!

Current behavior

I did some testing for this change #12678 and fix does not seem to be fully correct, right now asserts keyword is not included into range,

this issue seem to be present only when this keyword is used, in other cases range is correct

related ticket #12676

Input Code

class AssertsFoo {
  isBar(): asserts this is string {
    return;
  }
}

Expected behavior
asserts keyword should be included into range of TSTypePredicate

Environment

• Babel version(s): [e.g. v7.12.0]
• Node/npm version: [e.g. Node 12/npm 7]
• OS: [e.g. macOS 10.15.4, Windows 10]
• Monorepo: [e.g. yes/no/Lerna]
• How you are using Babel: [e.g. webpack, rollup, parcel, babel-register]

[babel-bot]

Hey @armano2! We really appreciate you taking the time to report an issue. The collaborators on this project attempt to help as many people as possible, but we're a limited number of volunteers, so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack community that typically always has someone willing to help. You can sign-up here for an invite."

[fedeci]

Working on this, the solution should be similar to #12757