update doc/en/**

doc/en/scripting/builtins/libtime.md

@@ -0,0 +1,13 @@
+# *time* library
+
+```python
+time.uptime() -> float
+```
+
+Returns time elapsed since the engine started.
+
+```python
+time.delta() -> float
+```
+
+Returns time elapsed since the last frame.