unit test for chromosome option

[Levi Waldron]

@Aggarwal-Ayush has added examples, e.g.

HGNChelper/R/checkGeneSymbols.R

Line 62 in be6f7a9

 #' checkGeneSymbols("Sip1", chromosome=14) # should give error when hgnc.table does not contain chromosome 

Now create formal unit tests in the tests/ directory to make sure the expected behavior occurs.

[Sehyun Oh]

Chromosome argument related unit tests were moved/updated in tests/testthat/test_checkGeneSymbols.R and confirmed by GHA R-CMD-check. 6e55d80