Previously, bus elements that were not instantiated as individual nets
could not connect to each other. This caused issues for complex
schematics where busses needed to connect to other busses with elements
that resolved to the same net names. Functionally, this means mixing
bus elements, which we will replace with first-class elements in version
8 but currently can only be accomplished either by using bus aliases and
this patch or by individually instantiating each bus element as a
local label
Fixes https://gitlab.com/kicad/code/kicad/issues/14300
16b4ec3c7e