Bug 10982: fix link to IFLA UNIMARC documentation in Cataloging

Bug 10982: fix link to IFLA UNIMARC documentation in Cataloging

In Cataloging, a ? opens a documentation page on IFLA web site. The current
implementation rely on the tag tab to select the appropriate IFLA
documentation web page. It doesn't work when UNIMARC tag are displayed
in a tab which digit is different for tag first digit.

To reproduce the bug:

  - Modify default framework, put all 200 subfields in tab 1
  - Add a new biblio record
  - Click on ? on 200 field
   => Wrong IFLA page is opened

Apply the patch and retry...

Signed-off-by: Bernardo Gonzalez Kriegel <bgkriegel@gmail.com>
Simple fix. Work as described. No koha-qa errors

Test on UNIMARC install
1) Switched all 2xx tags to tab 1
2) press any 2xx ?, wrong page
3) patch applied
4) links are now correct

Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>