IceNeat

anchor of md-menu doesn't support id that starts with digits

3

### What is affected? Component ### Description I think in this line https://github.com/material-components/material-web/blob/main/menu/internal/menu.ts#L329-L330 could use `` querySelector(`#${CSS.escape(this.anchor)}`) `` or `document.getElementById(this.anchor)` so that id starts with digits would cause no issue....