antlr4 lacks automatic module name, which is inconsistent to antlr4-runtime

[Stewori]

The newest antlr4 jar file distributed on maven central, i.e. https://repo1.maven.org/maven2/org/antlr/antlr4/4.13.1/antlr4-4.13.1.jar, lacks an automatic module name in its manifest file. That is inconsistent to the behavior of antlr4-runtime, which does explicitly declare the line

Automatic-Module-Name: org.antlr.antlr4.runtime

in its MANIFEST.MF file. I believe that artifacts of a common roof project should ideally obey a common module name structure. Therefore I recommend that a similar line, i.e.

Automatic-Module-Name: org.antlr.antlr4

should be declared in the MANIFEST.MF file of (future) distribution jar files of the https://repo1.maven.org/maven2/org/antlr/antlr4 maven artifact.

I am aware of #2946, which is related, but rather old and does not address specifically and explicitly the inconsistence pointed out here. I also acknowledge that this is a low priority issue and just a small consistency concern. Please feel free to track it simply as a reminder to adjust this bit for the next release.