grammar.js

module.exports = grammar({
	name: 'wikitext',

	rules: {
		// ... other rules ...
		h1_heading: $ => seq(
			$.h1_marker,
			optional(repeat1(/\s/)),
			$.heading_text,
			optional(repeat1(/\s/)),
			$.h1_marker
		),

		h1_marker: $ => '=',

		heading_text: $ => /[^=\n]+/,

		// ... other rules ...
	},


	// ... other grammar properties ...
});