fix: fix JSON within core commands and update highlighting

[hkimura-intersys]

Overview

A bug was found where the return statement wasn't parsing JSON objects correctly. This PR fixes that bug and updates highlighting.

Details

The return statement wasn't being parsed correctly (this was a special case where the scanner was messing up and registered { as an argumentless loop, when it shouldn't since it is json):

This led me to realize this should be fixed for many of the commands. I added a new function 
build_command_rule_argumentful_block_allowed to core that doesn't register { as a block, and thus parses json objects as expected.

This new function replaces build_command_rule_argumentful for the following commands: write,lock,read,open,close,use,throw,break,return,quit,goto,hang,xecute,view,
zkill,zn,zsu,ztrap,zwrite,zz.

With this change, JSON objects are parsed as expected:

Highlighting Updates

• Mirrored the way JSON is highlighted in its tree-sitter grammar by highlighting keys differently than values.

Testing

See the corresponding workflows:

• CI (parser/query tests)
• Fuzz Scanner
• Lint (grammars/queries)
• Publish (rust, npm, python) : published version 1.6.3 which contains these changes.