[lldb][Docs] Remove unnecessary colon in title

Author: DavidSpickett

lldb/docs/use/python-reference.rst

@@ -885,8 +885,8 @@ When the program is stopped at the beginning of the 'read' function in libc, we
   (lldb) frame variable
   (int) fd = 3
 
-Writing Target Stop-Hooks in Python:
-------------------------------------
+Writing Target Stop-Hooks in Python
+-----------------------------------
 
 Stop hooks fire whenever the process stops just before control is returned to the
 user.  Stop hooks can either be a set of lldb command-line commands, or can