Navigate to the top-level function's definition where the cursor is located

[usfbih8u]

No description provided.

[usfbih8u]

This PR uses documentSymbols and ranges to find the function where the cursor is located.

This is a functionality that I find useful when I am in a long function.

In languages that use {} for scopes, I created a plugin that allows me to do that (and more), but in Lua, I need something different.

If you find this out of scope (it is, in my opinion, but useful) for the project, feel free to close this PR. I will keep it for myself.

The name could be better, but if you are not merging it, I don't care about the name.

[Andriamanitra]

If you find this out of scope (it is, in my opinion, but useful) for the project, feel free to close this PR. I will keep it for myself.

I don't mind adding functionality that is not directly provided by the LSP.

I'm not sure about the implementation though, I feel like there is a way to make it more widely useful by making it more generic. I'll need to think about it some more.

[usfbih8u]

Obviously, it is not generic at all; it is tailored specifically to my personal use case.

Feel free to take this PR in a different direction in the future if you want to.

[usfbih8u]

The LSP specification states that in SymbolInformation[], there is no range that can "be used to re-construct a hierarchy of the symbols." However, after using clangd and receiving SymbolInformation[], I noticed that sym.location.range is, in fact, the range of the function.

I do not know if this is a clangd thing or if it is widespread enough to be usable. It could be reverted otherwise.