Update git submodules
- Update extensions/Math from branch 'REL1_39' to 04c41de5dd3fc102dd8a5ce20fd8b781851f8071
- Localisation updates from https://translatewiki.net.
Change-Id: I50964b29f413004a07d6f2f3b620030616a8e23a
- Localisation updates from https://translatewiki.net.