Improved documentation as advised by @jmtcsngr

bin/npg_samplesheet_generator_NovaSeqXSeries

@@ -57,6 +57,12 @@ npg_samplesheet_generator_NovaSeqXSeries
                 DRAGEN analysis can deal with a limited number of distinct
                 configurations. Set this attribute if processing off-board.
 
+  C<dragen_software_version> -
+                DRAGEN software version to use, optional
+
+  C<file_name> -
+                name of the samplesheet CSV file, optional
+
 =head1 DESCRIPTION
 
 Generates a samplesheet for the NovaSeq Series X Illumina instrument and

lib/npg/samplesheet/novaseq_xseries.pm

@@ -201,7 +201,7 @@ has 'read_length' => (
   'is'         => 'ro',
   'lazy_build' => 1,
   'required'   => 0,
-  'documentation' => 'An array containing the length of the forward and the ' .
+  'documentation' => 'An array containing the length of the forward and ' .
                      'reverse read',
 );
 sub _build_read_length {
@@ -585,15 +585,17 @@ used when processing the sequencing data. Must adhere to the following
 requirements:
 
 - Must be same number of fields (delimited by semicolon) as sequencing and
-  indexing reads specified in RunInfo.xml or Reads section.
+  indexing reads specified in RunInfo.xml or 'Reads' section.
 
-- Indexing reads are specified with I, sequencing reads are specified with
-  Y, UMI cycles are specified with U, and trimmed reads are specified with N.
+- Indexing reads are specified with 'I',
+  sequencing reads are specified with 'Y',
+  UMI cycles are specified with 'U',
+  and trimmed reads are specified with 'N'.
 
 - The number of cycles specified for each read must equal the number of cycles
   specified for that read in the RunInfo.xml file.
 
-- Only one Y or I sequence can be specified per read.
+- Only one 'Y' or 'I' sequence can be specified per read.
 
 =cut