fix(types): add missing @return annotations

runtime/lua/vim/diagnostic.lua

@@ -1485,7 +1485,7 @@ end
 ---@param bufnr? integer Buffer number to get diagnostics from. Use 0 for
 ---                      current buffer or nil for all buffers.
 ---@param opts? vim.diagnostic.GetOpts
----@return table : Table with actually present severity values as keys
+---@return table<integer, integer> : Table with actually present severity values as keys
 ---                (see |diagnostic-severity|) and integer counts as values.
 function M.count(bufnr, opts)
   vim.validate('bufnr', bufnr, 'number', true)

runtime/lua/vim/lsp/client.lua

@@ -1191,6 +1191,7 @@ end
 --- Note: Some language server capabilities can be file specific.
 --- @param method vim.lsp.protocol.Method.ClientToServer | vim.lsp.protocol.Method.Registration
 --- @param bufnr? integer
+--- @return boolean
 function Client:supports_method(method, bufnr)
   -- Deprecated form
   if type(bufnr) == 'table' then