tests/test-gendoc.t

documentation: add some internals documentation about bid merge

This is an important algorithm that was only documented on the wiki so far.

Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.

Differential Revision: https://phab.mercurial-scm.org/D8711

#require docutils
#require gettext

Test document extraction

  $ HGENCODING=UTF-8
  $ export HGENCODING
  $ { echo C; ls "$TESTDIR/../i18n"/*.po | sort; } | while read PO; do
  >     LOCALE=`basename "$PO" .po`
  >     echo "% extracting documentation from $LOCALE"
  >     LANGUAGE=$LOCALE "$PYTHON" "$TESTDIR/../doc/gendoc.py" >> gendoc-$LOCALE.txt 2> /dev/null || exit
  > 
  >     if [ $LOCALE != C ]; then
  >         if [ ! -f $TESTDIR/test-gendoc-$LOCALE.t ]; then
  >             echo missing test-gendoc-$LOCALE.t
  >         fi
  >         cmp -s gendoc-C.txt gendoc-$LOCALE.txt && echo "** NOTHING TRANSLATED ($LOCALE) **"
  >     fi
  > done; true
  % extracting documentation from C
  % extracting documentation from da
  % extracting documentation from de
  % extracting documentation from el
  % extracting documentation from fr
  % extracting documentation from it
  % extracting documentation from ja
  % extracting documentation from pt_BR
  % extracting documentation from ro
  % extracting documentation from ru
  % extracting documentation from sv
  % extracting documentation from zh_CN
  % extracting documentation from zh_TW