feat: allow caching and resuming picker (#1051)

* expose `cache_picker` in telescope.setup to configure caching, see `:h telescope.defaults.cache_picker`
* add builtin.resume and builtin.pickers picker

lua/telescope/algos/linked_list.lua

@@ -215,4 +215,41 @@ function LinkedList:ipairs()
   end
 end
 
+function LinkedList:truncate(max_results)
+  if max_results >= self.size then
+    return
+  end
+
+  local current_node
+  if max_results < self.size - max_results then
+    local index = 1
+    current_node = self.head
+    while index < max_results do
+      local node = current_node
+      if not node.next then
+        break
+      end
+      current_node = current_node.next
+      index = index + 1
+    end
+    self.size = max_results
+  else
+    current_node = self.tail
+    while self.size > max_results do
+      if current_node.prev == nil then
+        break
+      end
+      current_node = current_node.prev
+      self.size = self.size - 1
+    end
+  end
+  self.tail = current_node
+  self.tail.next = nil
+  if max_results < self.track_at then
+    self.track_at = max_results
+    self.tracked = current_node.item
+    self._tracked_node = current_node
+  end
+end
+
 return LinkedList