* json: default additionalProperty to true
* json: don't force additional props after normal properties!
* json: allow space after enum/const
* json: update pydantic example to set additionalProperties: false
* json: prevent additional props to redefine a typed prop
* port not_strings to python, add trailing space
* fix not_strings & port to js+py
* Update json-schema-to-grammar.cpp
* fix _not_strings for substring overlaps
* json: fix additionalProperties default, uncomment tests
* json: add integ. test case for additionalProperties
* json: nit: simplify condition
* reformat grammar integ tests w/ R"""()""" strings where there's escapes
* update # tokens in server test: consts can now have trailing space