Fixed crash while mgf parsing

[douweschulte]

I found a rare crash while reading MGF files. By the way the function Option::take does exactly what you are doing with mem::swap while being more main stream in other Rust code. I saw this same pattern at some other places in the code base so changing those might be warranted.

[douweschulte]

Root cause description

fixes where applied in the reverse order from this description

I figured out that the root cause is that in a recent update mzdata started parsing CHARGE=XX in mgf, as I used 2+ instead of +2 for the charge field the parsing broke down. After breaking down the parser had its state self.state as error and work as false. Because the error state was never checked the main parsing loop finished and an unfinished spectrum was returned and any further reading of the spectra will fail.

Additionally the error.unwrap() crashed in this case which in some way lead to a panic in a panic which fully crashed the annotator.

Description of changes

• Fixed crash when no error is saved in self.error
• Fixed MGF parser ignoring errors encountered during handling of the MGF line
• Updated MGF CHARGE parser to handle 2+
• Refactored some code to be more in line with Clippys suggestions and Rust idioms

[mobiusklein]

Thank you for fixing this. Please let me know when you're ready for this to be merged.

[douweschulte]

I am ready for merging.