merge annotation separators in fastq and fasta headers

[frederic-mahe]

vsearch --fastx_filter <(printf "@s;size=1;\nA\n+\nI\n") --eeout --fastqout - 2> /dev/null

The toy example above returns:

@s;size=1;;ee=0.0001
A
+
I

It might be cleaner to merge the annotation separators, i.e. write only one ; instead of two? This is a very minor point.