poedit: Fix reporting of notes for translators for Poedit 1.5.7.

Re #3485.
poedit: Fix script docstrings.
Update User Guide.
Merge branch 't3485' (Poedit 1.5.7 changes).

It seems that when this was merged, some of the later commits were accidentally missed, including the fix for the Report notes for translators command.
Translators, please note that this merge introduces some minor changes to translatable strings for Poedit and the User Guide.
Fixes #3485. For real this time.
api.setNavigatorObject: if the review mode is document and the object has no treeInterceptor or its passThrough (or the treeInterceptor is not ready), set the review mode to object. The extra isReady check stops subsiquant exceptions in event_becomesNavigatorObject when a virtualBuffer is not yet ready. Fixes #3594
Adobe Reader virtualBuffer's getIdentifierFromNVDAObject: raise LookupError if the given object is not an AcrobatNode (i.e. does not have an accID property) rather than throwing  an AttributeError and mucking up the review cursor. Seen when focusing on combo boxes.
l10n: updated translations from svn rev 12904.
strip automatically generated source code line numbers from po files.
displayModel.DisplayModelTextInfo._getOffsetsFromNVDAObject: raise LookupError instead of RuntimeError when an object has no location. Allows switching to screen review when the navigator object has no screen location. Fixes #3454
Merge commit 'fetch_head' into jpbranch