bib-format: Fix line wrapping (iteration and commas)

* Fix jumping back to label to process more than two lines.
* Take care of trailing commas that do not end the entry.
13 jobs for master in 1 minute and 23 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  Test
passed bib-conva_test #102263

00:00:20

passed bib-convl_test #102264

00:00:20

passed bib-convu_test #102265

00:00:21

passed bib-extract_test #102266

00:00:15

passed bib-format_test #102267

00:00:15

passed bib-jabbr_test #102268

00:00:37

passed bib-keyinsert_test #102269

00:00:29

passed bib-name_test #102270

00:00:28

passed bib-order_test #102271

00:00:18

passed bib-pdfinsert_test #102272

00:00:12

passed bib-separate_test #102273

00:00:11

passed bib-txt_test #102274

00:00:18

passed bib-unite_test #102275

00:00:10