change output quant file to an optional argument

src/salmon/salmon_quant/config.vsh.yaml

@@ -24,7 +24,7 @@ argument_groups:
         description: |
           Format string describing the library.
           The library type string consists of three parts: 
-          1. Relative orientation of the reads: This part is only provided if the library is paired-end, THe possible options are
+          1. Relative orientation of the reads: This part is only provided if the library is paired-end, The possible options are
             I = inward
             O = outward
             M = matching
@@ -118,7 +118,7 @@ argument_groups:
         direction: output
         description: |
           Salmon quantification file.
-        required: true
+        required: false
         example: quant.sf
 
   - name: Basic options
@@ -327,7 +327,7 @@ argument_groups:
           If this option is provided, then the selective-alignment results will be written out in SAM-compatible format. By default, output will be directed to stdout, but an alternative file name can be provided instead.
       - name: --mapping_sam
         type: file
-        description: Path to file that should output the selective-alignment results in SAM-compatible format. THis option must be provided while using --write_mappings
+        description: Path to file that should output the selective-alignment results in SAM-compatible format. This option must be provided while using --write_mappings
         required: false
         direction: output
         example: mappings.sam