Add link to memoryview documentation

Author: pbugnion

docs/source/examples/Widget List.ipynb

@@ -1054,7 +1054,7 @@
     "#=> ]\n",
     "```\n",
     "\n",
-    "The contents of the file uploaded are in the value of the `content` key. They are a memory view:\n",
+    "The contents of the file uploaded are in the value of the `content` key. They are a [memory view](https://docs.python.org/3.8/library/stdtypes.html#memory-views):\n",
     "\n",
     "```python\n",
     "[uploaded_file] = uploader.value\n",
@@ -1069,7 +1069,7 @@
     "#=> b'This is the content of example.txt.\\n'\n",
     "```\n",
     "\n",
-    "You can get the contents as a string if the file is a text file (more precisely, if the file can be decoded as UTF-8):\n",
+    "If the file is a text file, you can get the contents as a string by decoding it:\n",
     "\n",
     "```python\n",
     "import codecs\n",