Drop no longer needed modification of the C++ grammar

[marco-c]

We should be able to drop

rust-code-analysis/tree-sitter-mozcpp/grammar.js

Lines 19 to 38 in 1c3c663

	operator_name: $ => token(seq(
	'operator',
	/\s*/,
	choice(
	'+', '-', '*', '/', '%',
	'^', '&', '|', '~',
	'!', '=', '<', '>',
	'+=', '-=', '*=', '/=', '%=', '^=', '&=', '|=',
	'<<', '>>', '>>=', '<<=',
	'==', '!=', '<=', '>=',
	'&&', '||',
	'++', '--',
	',',
	'->*',
	'->',
	'()', '[]',
	'new', 'delete',
	'new[]', 'delete[]',
	)
	)),

as it should be part of upstream now.

We should try to drop it, regenerate grammar and check that there are no differences in metrics.