Remove ability to translate some portions of manual

[strk]

Things tend to break when translators translate too much. Some things should not be translatable. Function synopsis is one of these things.

There is also some support at the weblate level to make specific strings untranslatable, which would also be good to use, but I'm not sure how to do that programmatically.

For funcsynopsis tags we migth be able to filter those tags out BEFORE calling xml2pot

[Sandro Santilli <strk@…>]

In 2e149c7/git:

[de] Fix ST_Collect synopsis translation

References #5440

[strk]

A possible good candidate, although it would introduce a new dependency:

xmlstarlet - command line XML toolkit

Using XSLT would require having all entities defined

[strk]

Same problem with xmlstarlet:

xmlstarlet ed -d '//funcsynopsis' reference_output.xml
[..]
reference_output.xml:1739.20: Entity 'Z_support' not defined
                <para>&Z_support;</para>
                                 ^

[strk]

I filed a request upstream: ​https://invent.kde.org/sdk/poxml/-/issues/1

[strk]

We have some occurrences of <programlisting> inside <para>, which make them mixed with text we do want to translate in the template file. To get a list:

grep -l '<programlisting>' doc/po/templates/*.pot

[strk]

I'd try to move to xgettext to extract text and ITS rules to mark untranslatable snippets:

​https://www.gnu.org/software/gettext/manual/html_node/Preparing-ITS-Rules.html#Preparing-ITS-Rules

See also #5074

[strk]

xgettext, like itstool, also suffers use of entities:

xgettext --its postgis.its administration.xml 
xgettext: cannot read administration.xml: Entity 'last_release_version' not defined

I guess we'd better wait to migrate all our manual to docbook5 to better deal with localization.

[strk]

Another option I was thinking would be we strip blocks of lines in .pot file starting whith #. Tag: programlisting and ending on blank line or end of file

[Sandro Santilli <strk@…>]

In 109084be/git:

Skip translation of some xml tags

For now we skip these tags:

• programlisting
• screen
• funcsynopsis

Closes #5440

[strk]

We still have some programlisting in para, which I think we should remove. See also ​https://github.com/asciidoctor/docbookrx/issues/41#issuecomment-222571929