Add leucine to chymo cleavage motif (#759)

* correct Within calculation

* update unit tests

* this is the spot

* add space

* update proteasesTsv

---------

Co-authored-by: MICHAEL SHORTREED <mrshortreed@wisc.edu>

mzLib/Proteomics/ProteolyticDigestion/proteases.tsv

@@ -1,8 +1,8 @@
 Name	Sequences Inducing Cleavage	Sequences Preventing Cleavage	Cleavage Terminus	Cleavage Specificity	PSI-MS Accession Number	PSI-MS Name	Site Regular Expression	Cleavage Mass Shifts	Notes
 Arg-C	R|			full	MS:1001303	Arg-C	(?<=R)(?!P)		
 Asp-N	|D			full	MS:1001304	Asp-N	(?=[BD])		
-chymotrypsin (don't cleave before proline)	"F[P]|,W[P]|,Y[P]|"			full	MS:1001306	Chymotrypsin	(?<=[FYWL])(?!P)		
-chymotrypsin (cleave before proline)	"F|,W|,Y|"			full	MS:1001306	Chymotrypsin	(?<=[FYWL])		
+chymotrypsin (don't cleave before proline)	"F[P]|,W[P]|,Y[P]|,L[P]|"			full	MS:1001306	Chymotrypsin	(?<=[FYWL])(?!P)		
+chymotrypsin (cleave before proline)	"F|,W|,Y|,L|"			full	MS:1001306	Chymotrypsin	(?<=[FYWL])		
 CNBr	M|			full	MS:1001307	CNBr	(?<=M)	Homoserine lactone on M	
 elastase	"A|,V|,S|,G|,L|,I|"			full		Elastase	(?<=[AVSGLI])		
 Glu-C	E|			full