Add ..= to the parser
Add ..= to libproc_macro
Add ..= to ICH
Highlight ..= in rustdoc
Update impl Debug for RangeInclusive to ..=
Replace `...` to `..=` in range docs
Make the dotdoteq warning point to the ...
Add warning for ... in expressions
Updated more tests to the ..= syntax
Updated even more tests to the ..= syntax
Updated the inclusive_range entry in unstable book
End-less ranges (`a...`) don't parse but bad syntax extensions could
conceivably produce them. Unbounded ranges (`...`) do parse and are
caught here.
The other panics in HIR lowering are all for unexpanded macros, which
cannot be constructed by bad syntax extensions.
Mostly copy the tests from half-open ranges, adding some more for
DoubleEndedIterator and ExactSizeIterator.
Also thoroughly (I think) test that the feature gates are working.
