doc update

Author: wang0618

docs/cookbook.rst

@@ -38,7 +38,7 @@ Output pandas dataframe
 Output Matplotlib figure
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Simply do not call ``matplotlib.pyplot.show``, directly save the figure to in-memory buffer and output the buffer
+Instead of using ``matplotlib.pyplot.show()``, to show matplotlib figure in PyWebIO, you need to save the figure to in-memory buffer fist and then output the buffer
 via :func:`pywebio.output.put_image`:
 
 .. exportable-codeblock::

pywebio/output.py

@@ -1599,7 +1599,7 @@ def popup(title, content=None, size=PopupSize.NORMAL, implicit_close=True, closa
 
     :param str title: The title of the popup.
     :type content: list/str/put_xxx()
-    :param content: The content of the popup can be a string, the put_xxx() calls , or a list of them.
+    :param content: The content of the popup. Can be a string, the put_xxx() calls, or a list of them.
     :param str size: The size of popup window. Available values are: ``'large'``, ``'normal'`` and ``'small'``.
     :param bool implicit_close: If enabled, the popup can be closed implicitly by clicking the content outside
         the popup window or pressing the ``Esc`` key. Default is ``False``.