Enhancement: Clarify need to switch to undeground mode

[originalfoo]

This is mainly for lane connector tool, but probably other tools too...

See also: #1330

Just showing a 🚫 cursor isn't enough to explain to user that they need to be in underground mode to customise that node/segment etc. From user perspective it's "There's a node here but you're not allowed to change it" - and it doesn't explain why?

For node-specific tools, it might be better not to show the node circle and, instead, show a down arrow - similar to what's planned for speed limits tool:

The down arrow could become the consistent way across all tools to indicate something underground.

In this case, the 🚫 cursor would no longer be required because we wouldn't be showing a tempting node to user any more; we'd be showing an indicator that something lurks underground. We could potentially show mouse tooltip when they hover down arrow with text explaining what it is (maybe only if tutorials are enabled?) etc.

[aTadnMad]

ok. so how does one "go underground"?

[krzychu124]

just like in vanilla, with PageDown key, it's configurable since v11.6.5.1

[aTadnMad]

just like in vanilla, with PageDown key, it's configurable since v11.6.5.1

no, no - for lane connecting :p

[krzychu124]

Ok, so you didn't try.