fix: "goto > Declaration or Usages" to show references when ⌘B on definitions

[aridclown]

IntelliJ's "Go to > Declaration or Usages" (⌘B) shortcut is a commonly used shortcut that, in general, should display usages when triggered from the declaration itself.

In the LSP handler, we only call textDocument/definition, so pressing ⌘B on a declaration has no effect (tested with LuaLS).

A few things to note:

• As discussed in Open references if definition result has the same range than clicked offset #531, this change tentatively aims to instruct LSPGotoDeclarationHandler to fall back to textDocument/references: if the definition we receive overlaps the caret, we reuse the same reference list and popup that the "Go to → LSP References" command uses.
• Ctrl-hover still just underlines the symbol, but a click now opens the rich usages panel instead of silently failing.
• To avoid duplicating code, we introduced a tiny LSPReferenceCollector helper and pointed both the standalone reference action and the new fallback at it.

PS: I'm not an expert in LSP4IJ, so this is a tentative implementation. I tested it, and it works, but my main goal here is to restart the conversation on this issue and work out a solution, as this is a much-desired feature.

[angelozerr]

Thanks so much for your contribution.

Let me some times to test and study your PR.

Please fix your commit message by adding first fix:

[aridclown]

Hey @angelozerr, did you happen to have a chance to look this up? Sorry for pushing on this, but it would be a very welcome addition to the plugin for our setup over here 🙏

[angelozerr]

@aridclown I am sorry I am super busy with other topics but I promise you I will try your PR.

The only thing which is really annoying is that it doesn't follow the standard behavior of IJ since IJ should consume references autoamticly but for some reason it doesn't use it