Update_writing_using_seqtk01.rst

-A replaced the -a as mentioned in the option section of seqtk seq, despite -a just did the job!!!!
A matter of consistency!!
as in:
galaxyproject#561

Author: ramezrawas

docs/_writing_cwl_intro.rst

@@ -30,7 +30,7 @@ but you will still need to open up the editor and fill out the command, describe
 input parameters, tool outputs, writeup a help section, etc....
 
 The ``tool_init`` command can do a little bit better than this as well. We can
-use the test command we tried above ``seqtk seq -a 2.fastq > 2.fasta`` as
+use the test command we tried above ``seqtk seq -A 2.fastq > 2.fasta`` as
 an example to generate a command block by specifing the inputs and the outputs
 as follows.
 
@@ -40,7 +40,7 @@ as follows.
                         --cwl \
                         --id 'seqtk_seq' \
                         --name 'Convert to FASTA (seqtk)' \
-                        --example_command 'seqtk seq -a 2.fastq > 2.fasta' \
+                        --example_command 'seqtk seq -A 2.fastq > 2.fasta' \
                         --example_input 2.fastq \
                         --example_output 2.fasta
 
@@ -60,7 +60,7 @@ tool is generated.
                         --cwl \
                         --id 'seqtk_seq' \
                         --name 'Convert to FASTA (seqtk)' \
-                        --example_command 'seqtk seq -a 2.fastq > 2.fasta' \
+                        --example_command 'seqtk seq -A 2.fastq > 2.fasta' \
                         --example_input 2.fastq \
                         --example_output 2.fasta \
                         --container 'dukegcb/seqtk' \