fix(Examples): address a typo in one of the examples

This commit fixes a typo in the module docstring of the Floats example.

Refs: #1882

examples/full-screen/simple-demos/floats.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 """
-Horizontal split example.
+Floats example.
 """
 
 from prompt_toolkit.application import Application