fixes #282: preserve position in "identity" variants (e.g., norm(c.123A>A) => c.123= rather than c.=)
fixes #282: preserve position in "identity" variants (e.g., norm(c.123A>A) => c.123= rather than c.=)

biocommons/hgvs,biocommons/hgvs,biocommons/hgvs,biocommons/hgvs