Prior to this change the "Save As.." command would take a different action
based on the state of the editor which could be confusing. There are now
separate commands for saving the currently selected library or symbol.
CHANGED: The implicit save as menu entry which would save the currently
selected library if no symbol was selected or the current symbol to a
different library. There are now separate save as commands for libraries
and symbols to make it obvious what is being saved.
1) Zero out selection in tree when canvas captures focus so that
save/save as actions will go to canvas, not tree item.
2) Make save do a save to schematic when the canvas symbol is from
the schematic.
3) Copy fields when doing a save to schematic (setting the lib part
doesn't update them on its own).
4) Remove no-longer-necessary calls to update schematic after
saving symbols (the schematic symbols are no longer hot-linked).
Fixes https://gitlab.com/kicad/code/kicad/issues/6763
Wayne Stambaugh
Jeff Young