Function isRNA

isRNA(nucleicAcid): nucleicAcid is RNA
Type guard for checking if a nucleic acid is RNA
Parameters
- nucleicAcid: NucleicAcid
  The nucleic acid to check
Returns nucleicAcid is RNA
True if the nucleic acid is RNA, false otherwise
Example
```
 //pass an RNA object
 isRNA(new RNA()); //returns true

 //pass an DNA object
 isRNA(new DNA()); //returns false
```
- Defined in src/utils/nucleic-acids.ts:99