USI generation bug

[benpullman]

There's a bug when a mod is on the second to last amino acid of the spectrum, the closing bracket is after the final amino acid, not before it. For example: mzspec:PXD010154:01284_D01_P013188_B00_N04_R1:scan:38131:TTGIVLDSGDGVTHNVPIYEGYALPHAIM[+15.994915R]/3

[benpullman]

This code for converting inspect format to proforma is not in the python_ms_utilities repository, the fix should involve moving that function into that codebase.