signatures: show all overloads

[hfn92]

with this change the signature help should show all signatures that are possible given the current parameters.
This is useful for languages that support function overloading.

Given

void fn_ov();
void fn_ov(int i, float f, float f2);
void fn_ov(int i, float f);
void fn_ov(int i);

it should show:

[Saghen]

Thanks for this! Maybe there should be a limit on how many signatures we show? And maybe we should be smart about which signatures we prune (i.e. prefer fewer args, but filter out any signatures with less args than currently typed)

[Saghen]

local details = type(opts.detail) == 'string' and { opts.detail } or opts.detail
details = require('blink.cmp.lib.utils').deduplicate(details)

[hfn92]

@Saghen From what I can tell the list we get already contains only the possible signatures. E.g in my example fn_ov() and fn_ov(int i) are ignored because we are already at arg 2.

If you want I can add an option for the max amount of signatures. But I think this is already implicitly handled by blink.cmp.SignatureWindowConfig.max_height. I tested with 20 signatures but it will only show 10 lines, which is the default. Increasing max_height to >20 will then show everything. (I think this is how https://github.com/ray-x/lsp_signature.nvim works as well)

[Saghen]

Thanks!