Improve NameCheker c.6611_6612insA warning

[jtdendunnen]

Using NM_004006.2:c.6611_6612insA in the NameChecker gives as warning:
Insertion of A at position 6855_6856 was given, however, the HGVS notation prescribes that it should be a duplication of A at position 6855_6855.
I agree that lower on the page c.6611dup is given but this is easily missed.

Users will not understand how 6611_6612 relates to 6855_6856. In addition "duplication of A at position 6855_6855" is not correct. Suggest to change to e.g.:
Insertion of A at position n.6855_6856 was given, however, the HGVS notation prescribes that it should be a duplication of A at position n.6855.

Even better would be to give:
Insertion of A at position c.6611_6612 was given, however, the HGVS notation prescribes that it should be a duplication of A at position n.6611.