Hover: Add links to referenced types when possible

[FnControlOption]

Inspired by rust-analyzer, this PR adds "Go to <type>" in hover pop-ups:

[Techatrix]

Great work, but I found some weird behavior when hovering over type declarations:

// example_file.zig
const SomeType = struct {};
const Self = @This();

If you hover on SomeType, you will get Go to *SomeType*
If you hover on Self, you will get Go to *example_file*

[FnControlOption]

Great work

Thanks, I appreciate it 😄

I found some weird behavior when hovering over type declarations:

// example_file.zig
const SomeType = struct {};
const Self = @This();

If you hover on SomeType, you will get Go to *SomeType* If you hover on Self, you will get Go to *example_file*

I have an idea for avoiding redundant "Go to" for SomeType, but for Self, I'm not sure if it's possible to improve that without some refactoring. Currently, type aliases get completely resolved to whatever's the underlying type. (In the Zig stdlib, this isn't a problem since AFAIK file-level structs are named the same as normal structs, e.g. Allocator.zig) I have some local changes that adds .type_function variant to Type.data. Maybe I'll also need to add a .type_alias variant too.

[Techatrix]

If fixing the Self example is too complex, focusing just on SomeType should be fine, especially because that example is far more common to encounter.

Currently, type aliases get completely resolved to whatever's the underlying type. (In the Zig stdlib, this isn't a problem since AFAIK file-level structs are named the same as normal structs, e.g. Allocator.zig)

Maybe resolveVarDeclAlias is what you need. It will resolve aliases but not completely resolve its type.

I have some local changes that adds .type_function variant to Type.data.

functions in Type can already be represented with the Type.data.other but a more explicit case may be helpful.

[Techatrix]

Everything is in order except that you should use offsets.nodeToSlice instead of std.zig.Ast.getNodeSource because ZLS uses a custom lastToken function that is safe to use on ast with syntax errors.