Dynamic callbacks generating lists of tools should accept None context,
not crash on it.
Similar to what we do with dynamic RNA enums, when NULL/None context is
given, assume we are in 'introspection' mode and return as many things
as possible.
This is currently essentially used by i18n messages extraction tool
(where getting all possible entries is kind of mandatory ;) ).
Also add some initial missing tranlations for complex cases that cannot
be automated, there'll likely be more of that kind...
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