Single nucleotide duplications are not parsed correctly

[selkamand]

Thanks so much for your work on this package. Just wanted to report hgvs style single nucleotide duplications aren't considered valid by the parser at the moment:

library(hgvsParseR)

# [FAILS] Single Nucleotide Dup (genomic space)
parseHGVS('g.33229410dup')
#>            hgvs subject    type
#> 1 g.33229410dup genomic invalid

# [FAILS] Single Nucleotide Dup (coding space)
parseHGVS('c.20dup')
#>      hgvs subject    type
#> 1 c.20dup  coding invalid


# [WORKS] Mutli Nucleotide Dup (correctly parsed)
parseHGVS('c.20_23dup')
#>         hgvs subject        type start end
#> 1 c.20_23dup  coding duplication    20  23

sessionInfo()
#> R version 4.2.3 (2023-03-15)
#> Platform: x86_64-apple-darwin17.0 (64-bit)
#> Running under: macOS Big Sur ... 10.16
#> 
#> Matrix products: default
#> BLAS:   /Library/Frameworks/R.framework/Versions/4.2/Resources/lib/libRblas.0.dylib
#> LAPACK: /Library/Frameworks/R.framework/Versions/4.2/Resources/lib/libRlapack.dylib
#> 
#> locale:
#> [1] en_AU.UTF-8/en_AU.UTF-8/en_AU.UTF-8/C/en_AU.UTF-8/en_AU.UTF-8
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> other attached packages:
#> [1] hgvsParseR_0.2.0.9000
#> 
#> loaded via a namespace (and not attached):
#>  [1] rstudioapi_0.13   knitr_1.42        magrittr_2.0.3    R.cache_0.15.0   
#>  [5] rlang_1.0.6       fastmap_1.1.1     fansi_1.0.4       styler_1.7.0     
#>  [9] tools_4.2.3       xfun_0.37         R.oo_1.25.0       utf8_1.2.3       
#> [13] cli_3.6.0         withr_2.5.0       htmltools_0.5.4   yaml_2.3.7       
#> [17] digest_0.6.31     tibble_3.2.0      lifecycle_1.0.3   purrr_1.0.1      
#> [21] vctrs_0.5.2       R.utils_2.11.0    fs_1.6.1          glue_1.6.2       
#> [25] evaluate_0.20     rmarkdown_2.20    reprex_2.0.1      compiler_4.2.3   
#> [29] pillar_1.8.1      R.methodsS3_1.8.2 pkgconfig_2.0.3

^{Created on 2023-06-08 by the reprex package (v2.0.1)}