(it would behave like 'bone envelope resize' instead).
Issue comes from the fact this transform op shares some common points with both BoneResize
and BoneEnvelope operations. However, trying to re-use `TFM_BONE_ENVELOPE` itself in this case
is bad idea, since this mode gets stored in transform op and is directly re-used for redo,
by-passing the whole init phase that shall be done in `TFM_BONESIZE` mode... So now,
we add a real new mode, `TFM_BONE_ENVELOPE_DIST`, while keeping most of existing code
and all existing behavior.
This is slightly hackish - but was already anyway, and avoids creating a full new set of
function for pretty much the same thing. As a side note, also makes it possible to
resize envelope distance outside of envelope viewing mode (from py or by adding a custom
shortcut).
3b57f075a8