Add support for debugger Smart Step Into action via DAP `StepInTargets`

[SCWells72]

When playing with the DAP debugger, I noticed that it doesn't support the IDE's Smart Step Into action. It appears that LSP4IJ must be updated to support the DAP StepInTargets feature.

It's possible that no DAP server implementations actually support that feature, but I will say that I use Smart Step Into all the time in IntelliJ IDEA, particularly for usages of fluent/builder APIs, so it would be wonderful if LSP4IJ's DAP client supported it.

[angelozerr]

Hey Scott! Happy to meet you again.

Is there any chance to have some contribution?

[SCWells72]

It's very unlikely I'll be able to contribute unfortunately. These DAP-related issues I'm logging are a result of my integrating an external tool into my own plugin that allows local interactive debugging via DAP, so we're using LSP4IJ as the DAP client in the JetBrains IDE. This is the first time I've really spent significant time with your DAP implementation -- which is so far very impressive! -- and I'm just jotting down things that aren't working quite the way I'd expect and logging issues either here or in the other tool's public issue tracker depending on whether or not I know where the issue exists. So you might see a few others coming, but they're more to get things on the respective radar than anything critical (so far, at least).

[SCWells72]

@angelozerr, I may actually take a look at this after all. The DAP server that I'm primarily integrating is adding it, and once it's added there, I'll see if I can put together a PR for StepInTargets support in LSP4IJ's DAP client.

[angelozerr]

@angelozerr, I may actually take a look at this after all. The DAP server that I'm primarily integrating is adding it, and once it's added there, I'll see if I can put together a PR for StepInTargets support in LSP4IJ's DAP client.

Excellent news! Thanks @SCWells72 !

[angelozerr]

@SCWells72 I am working on this support.

Debugpy implements this StepInTargets so I have a sample. It uses label instead of line column. So if your dap server returns line column my code could have some bugs,