function replacer( match, p1, p2 ) {
		var out;

		if ( isString( p1 ) ) {
			if ( startsWith( p1, '## CLI' ) ) {
				return p1 + CLI_INSTALLATION_SECTION + ( p2 || '\n<!-- CLI usage documentation. -->\n' ) + '\n<section class="usage">';
			}
			if ( startsWith( p1, '<!-- C usage documentation. -->' ) ) {
				return p1 + '<section class="usage">';
			}
		}
		if ( noBundles ) {
			out = INSTALLATION_SECTION_BASIC;
		} else {
			out = INSTALLATION_SECTION_BUNDLES;
			out = out.replace( '<cli>', ( extractCLI ) ? INSTALLATION_SECTION_BUNDLES_CLI : '' );
		}
		out += '\n<section class="usage">';
		return out;
	}
Replacer function for inserting an install section before a usage section.

@private
@param {string} match - entire match
@param {string} p1 - first capture group
@param {string} p2 - second capture group
@returns {string} replacement