fxscript-vscode

Update copyright year and owner in LICENSE file

Change license from MIT to BSD Zero Clause License

lexer, tests, syntax: add support for escaped newlines and comments in line continuations with comprehensive tests and syntax highlighting

tests, parser: add diagnostics for `var` declarations with initial values and corresponding unit tests

tests, parser, lexer: add unit tests for multi-character operators, invalid operator handling, and improve parsing logic to prevent infinite loops