Add hierarchy lsp picker function

[ddaniel27]

Hey again! Recently I updated the plugin version from a loooong time without updating it (since now I have some time to deal with this kind of errors lol) and found that when you have multiple LSP's running in a buffer (like a code agent running aside the main LSP as in the screenshot) you will have an error calling the hierarchy lsp function since the handler chooses the first option from the returned clients.

This PR's adds a new function called pick_hierarchy_lsp_client just to pick the first LSP that has the server capabilities to use the callHierarchy related functions and has a relation with the current buffer. Let me know if more information is needed or any change required!

Thanks again for this amazing plugin! :)

EDIT:
Why I updated the plugin and what I want actually work is the definition_preview handler, I added that too in this PR, basically the actual response structure for result is a structure like this
local result = client:request_sync(method, params, timeout_ms or 1000, bufnr)

{                                                                                                                                                                                                                   
  result = { {                                                                                                                                                                                                      
      range = {                                                                                                                                                                                                     
        ["end"] = {                                                                                                                                                                                                 
          character = 23,                                                                                                                                                                                           
          line = 12                                                                                                                                                                                                 
        },                                                                                                                                                                                                          
        start = {                                                                                                                                                                                                   
          character = 5,                                                                                                                                                                                            
          line = 12                                                                                                                                                                                                 
        }                                                                                                                                                                                                           
      },                                                                                                                                                                                                            
      uri = "file:///home/ddaniel27/folder/go-project/internal/telemetry/attributes.go"                                                                                                                         
    } }                                                                                                                                                                                                             
}  

So, I updated the for loop where data is being populated, let me know your thoughts!

[ray-x]

hi @ddaniel27
Thanks for the PR
Just a question regarding root check. Otherwise, the changes look good to me.

[ray-x]

Thanks. I did not notice it was broken.

[ray-x]

Should it be?

if root and file:find(root, 1, true) == 1

Is there an example of lsp returns nil value for root_dir?

[ddaniel27]

My thoughts here were to not enforce root to cover edge cases where a bad configuration or architectural decisions of some LSP's could lead to a nil root_dir since the protocol allows it. Personally, I've no encounter these cases since all the LSP's that I use always have a defined root_dir but I'll let you decide here, if you think it's better to enforce root I can change it, let me know.

[ray-x]

LGTM, thanks!