GNParser fails when these (e.g., bis) are included in the author string

[dimus]

created by @mohamedabozeid at https://gitlab.com/gogna/gnparser/-/issues/61

parsing name has author with string bis included fails,
example: Hennediella microphylla (R.Br.bis) Paris
result: "unparsedTail": " (R.Br.bis) Paris"

[dimus]

created by @dimus at https://gitlab.com/gogna/gnparser/-/issues/43

have to add bis as a "suffix" ending for authorship.

R.Br.bis - Robert, of NZ Brown 1820-1906 according to IPNI, and there are quite a few other authors with
bis at the end