Add debug/watch/context to list of valid menu extension points

[adrianstephens]

This is a fix for #237750 - it just adds debug/watch/context to the list of valid menu extension points, which I presume was accidentally missed.

[gjsjohnmurray]

Does the title of this PR need correcting?

[sanqro]

👍

[connor4312]

Yea this should be fine, we already have similar menu extension points for other places variables/expressions are shown

[roblourens]

Did anybody try this?

The hard part about this is what the toolbar context should be. We need to define a new object which is safe to serialize and has a reasonable shape, and then that object is basically API

[adrianstephens]

I had a stab at the watch view context. In the interests of doing the least harm I added a toJSON to the Expression class which serializes it to the same thing the Variables view does - basically a session id and a DAP Variable. The Variables view seems to work around the same problem by using a global variable 'variableInternalContext'. I like my idea better!

While I was in there, I moved the data breakpoint commands to debugCommands.ts, and added them to the Watch view.

[thegecko]

Does this duplicate #212501

[adrianstephens]

@thegecko - huh; it looks like it does - although I'm only trying to bring the Watch panel to parity with Variables. Sorry I didn't notice yours.
Do you want to review mine and/or add to it? Do you have any insight into why yours went no further, or how we can prevent that happening to this one?

[adrianstephens]

@roblourens is there any realistic chance of you looking at this, or should I abandon it?