Add shortcuts help dialog

[syg]

[syg]

@bakkot The multipage baseline is failing in a way I don't quite understand. Maybe this shortcuts div needs to be inserted elsewhere?

[bakkot]

Running npm run update-baselines should fix baselines.

[syg]

Running npm run update-baselines should fix baselines.

Sorry, I meant update-baselines on multipage is failing in a way I don't understand:

  1) baselines
       test/baselines/sources/multipage.html:
     Error: non-clause children are not yet implemented: DIV
      at Spec.<anonymous> (lib/Spec.js:615:31)
      at Generator.next (<anonymous>)
      at /usr/local/google/home/syg/tc39/ecmarkup/lib/Spec.js:8:71
      at new Promise (<anonymous>)
      at __awaiter (lib/Spec.js:4:12)
      at Spec.buildMultipage (lib/Spec.js:559:16)
      at Spec.<anonymous> (lib/Spec.js:385:28)
      at Generator.next (<anonymous>)
      at fulfilled (lib/Spec.js:5:58)

[bakkot]

Sorry, I meant update-baselines on multipage is failing in a way I don't understand:

Ah. It's complaining because it sees the div as being basically a top-level clause, since it's at the top level and comes after the intro, and it doesn't know how to split that into a page.

Presumably we want this to be on every page of the multipage build, like the table of contents and unlike the rest of the boilerplate. So, easiest fix is to move this out of buildBoilerplate and into its own step of build, and then to add it to the tocEles list passed to buildMultipage so that it gets cloned onto every page like the table of contents does (which should at that point get renamed to something like sharedEles).

[syg]

Presumably we want this to be on every page of the multipage build, like the table of contents and unlike the rest of the boilerplate. So, easiest fix is to move this out of buildBoilerplate and into its own step of build, and then to add it to the tocEles list passed to buildMultipage so that it gets cloned onto every page like the table of contents does (which should at that point get renamed to something like sharedEles).

Perfect, thanks for the help.

[bakkot]

Ah jeeze, now it's failing because of a baseline-like test that isn't a baseline. I can push up a fix for that one.

[bakkot]

Nice, thanks!