Specify the jsdoc dependency, instead of expecting it to be installed globally

[kzar]

Background

With #5559 ensure_dependencies.py will install Node.js dependencies when a dependency is updated. So far we rely on JSDoc being installed globally, but now we can do things properly.

What to change

• Create the file buildtools/package.json with the following contents:

{
  "name": "buildtools",
  "repository": "https://hg.adblockplus.org/buildtools",
  "license": "MPL-2.0",
  "dependencies": {
    "jsdoc": "3.5.4"
  },
  "scripts": {
    "jsdoc": "jsdoc"
  }
}

• Modify buildtools/build.py to:
  • Remove the "This operation requires JsDoc 3 to be installed." text from the command description.
  • Call JSDoc as npm run-script jsdoc -- <jsdoc_arguments>.
• Add ^node_modules$ and /node_modules/ to buildtools/.hgignore and buildtools/.gitignore respectively. (Make sure ​the regexp syntax is used for the entry in .hgignore.)

[trev]

npm run-script doesn't run arbitrary commands, it only runs scripts specified in patterns.json. I updated the description with an approach that should work.

[tlucas]

Minor change, the buildtools' license is MPL 2.0

[trev]

I corrected the license identifier, it should be "MPL-2.0" rather than "MPL 2.0" - see ​https://spdx.org/licenses/

[tlucas]

As discovered during #5559, npm install (in version 8) generates a package-lock.json file. This should be committed along with the package.json.

[abpbot]

A commit referencing this issue has landed:
​Issue 5560 - Specify the JSDoc dependency explicitly