No reason specified when attempting to place benches, lamps, or bins on path with all four sides occupied

[SpartanFrederic104]

No reason specified when attempting to place benches, lamps, or bins on path with all four sides occupied

[harvito]

Since there's a reason in the case of a level crossing, probably a reason in case of no available unconnected edges is a good idea. Note that exact same reason appears in case of corner path additions (snowballs, jumping fountains) on a level crossing, but corner additions are allowed on all footpath, regardless of connected edges and corners:

I like SpartanFrederic104's suggestion "No available sides for path additions on this footpath tile," but could also go for a more succinct "No edges available" or "No unconnected edges" or "No unconnected edges available."
Some related testing notes:

• Connecting the last edge of a path tile with addition (eg bench) makes the bench disappear, but the path is still shown in tile inspector to have the addition. Deleting a connected path piece makes the bench appear again.
• Building a railroad track through a path with addition removes the addition entirely
• You're allowed to build signs accross level crossings (bug?)
• The game only allows you to build signs accross paths but doesn't prevent you from placing path all around an existing sign, and you can also delete the path on its non display side

[harvito]

looking into making PR

[harvito]

#21980 please review