ncbi_snp_query should not add 1 to position of indels (delins)

[VitorAguiar]

Hi, thanks for developing rsnps.

I just started using the package, but I notice that the documentation of ncbi_snp_query says that the function adds 1 to the positions of SNVs to match dbSNP. However, for indels (delins) it seems that the output position is off by 1 if you compare to the dbSNP page for the variant.

For example, compare the output below with dbSNP's website:

ncbi_snp_query("rs58275821")

https://www.ncbi.nlm.nih.gov/snp/?term=rs58275821