Merge changes from 4.10 of antlr4 RI

[daniellansun]

Hi @sharwell

The reference implementation of antlr4 was released 4.10 just now, how about merging the changes into the optimized fork?
https://github.com/antlr/antlr4/releases/tag/4.10

[daniellansun]

Hi @sharwell

4.11 was released, could you merge the changes into your optimized fork and release a new version too?
https://github.com/antlr/antlr4/releases/tag/4.11.0

[fedorusov]

Hi @sharwell

Any plans on keeping working on this repo, or will it be forsaken?

[daniellansun]

FYI, Apache Groovy 3+ ( https://github.com/apache/groovy ) uses the optimized fork of antlr4 too, in order to gain benefit from the latest changes of official antlr4, we have to merge the changes and release by ourselves for now:
#81
apache/groovy@26277ba