function replacer( match, p1, offset ) {
	p1 = lowercase( p1 );
	return ( offset === 0 ) ? p1 : capitalize( p1 );
}
Converts first capture group to uppercase.

@private
@param {string} match - entire match
@param {string} p1 - first capture group
@param {number} offset - offset of the matched substring in entire string
@returns {string} uppercased capture group