fix(watch): use old lsp supports method for v0.10.1 (#456)

* fix(watch): fixed neotest.watch starting problem

On the version v0.10.1, supports_method is still a table, rather than
a function. Code was trying to call a regular table field as a function,
resulting in following error:

attempt to call field 'supports_method' (a table value)

Now the type of the client.supports_method is checked beforehand,
instead of accessing the method right away.

* fix(watch): edge case in case neither client is found

* fix(watch): instead of type, checking the nvim version instead

Basically 1:1 code @rcasia proposed.

lua/neotest/consumers/watch/init.lua

@@ -32,14 +32,20 @@ neotest.watch = {}
 local function get_valid_client(bufnr)
   local clients = nio.lsp.get_clients({ bufnr = bufnr })
   for _, client in ipairs(clients) do
-    local has_definition_support = client.supports_method
-        and client.supports_method("textDocument/definition")
+    local has_definition_support
+    if nio.fn.has("nvim-0.10.1") == 0 then
       -- for compatibility with Neovim versions earlier than v0.10.1
-      or client.server_capabilities.definitionProvider
+      has_definition_support = client.server_capabilities ~= nil
+        and client.server_capabilities.definitionProvider
+    else
+      has_definition_support = client.supports_method.textDocument_definition({ bufnr = bufnr })
+    end
 
     if has_definition_support then
       logger.debug("Found client", client.name, "for watch")
       return client
+    else
+      logger.debug("Client for watch not found")
     end
   end
 end