With this PR, when pressing `I` in the viewport and the code
is unable to insert **ANY** keyframes, the user will be presented
with a single message detailing exactly why it has failed.
This PR promotes the functionality introduced in
#117449 into the header file so it can be used elsewhere.
The `CombinedKeyingResult` class is returned
from `insert_key_action` and `insert_key_rna`, and
used to produce a single report from the operator if it
failed to insert any keyframes.
In order to easily create a report from a `CombinedKeyingResult`
the function `generate_keyframe_reports_from_result`
has been moved into the class as `generate_reports`.
In addition to that the `UNABLE_TO_INSERT_TO_NLA_STACK` result
has been added. This notifies the user if keyframe insertion is not
possible due to NLA stack settings.
Pull Request: https://projects.blender.org/blender/blender/pulls/119201
956d8379a4