Using extension methods in dart:-libraries breaks dartdoc

[dcharkes]

Creating an issue to mark as D26.

Full issue here: dart-lang/dartdoc#2039 and dart-lang/dartdoc#2033

From @athomas: We'll have to revert the extension method API CLs tomorrow if this is not fixed, or we cannot make a release.

/cc @mit-mit, @sjindel-google, @mkustermann

[athomas]

We should revert/fixup release blockers immediately. We're already unlikely to have a good dev build tomorrow because the release build is broken today (and we will have a Google3 hash that can't be released externally).

[athomas]

Marking this as P0 until the release build is fixed (if we wanted to release 2.6 today, we couldn't because of this issue).

[dcharkes]

I added a diff to dart-lang/dartdoc#2039 that works around the problem, but I'm not sure whether that's the right fix.

I can try removing all the comments on the extension methods, to see if that works around it for now. (edit: removing all the /// [block] comments works.)

[mit-mit]

cc @jcollins-g

[dcharkes]

Original dartdoc issue: dart-lang/dartdoc#2033

[dcharkes]

I landed a workaround, the release build works, but has no resolved identifiers in the dartdoc comments on extension methods.

[vsmenon]

This is worked around, so no longer P0.