DOC: add admonition to every JupyterLite kernel

doc/source/conf.py

@@ -293,3 +293,14 @@
 
 global_enable_try_examples = True
 try_examples_global_button_text = "Try it in your browser!"
+try_examples_global_warning_text = (
+"""These interactive examples with JupyterLite are experimental and
+may not always work as expected. The execution of cells containing import
+statements will result in high bandwidth usage and may take a long time to
+complete.
+
+If you are on the latest version of the documentation, please install the
+latest version of PyWavelets to ensure the examples work as expected, via
+the following command:
+"""
+)