Visualization for scope types

[pokey]

• add a command "show scopes " eg "show scopes funk"
• will highlight all scopes on screen using semi-transparent background to make nesting visible
• could also do "show scope hierarchy" which would show hierarchy of all scope types containing given scope
• note these are cursorless scope types, not raw tree-sitter scope types
• could use this one for keyboard version and do it as the user types
• need to think of good api for scope types so that we can get this information easily
• could have "hint scopes " to make it disappear after a couple seconds, or after next command
• might be useful to map to a noise? not by default
• think about making it nonintrusive enough to leave on for a while
• update as you scroll?