IDLE: Fix typos in docs and comments (GH-13749)

diff --git a/Lib/idlelib/squeezer.py b/Lib/idlelib/squeezer.py
index 869498d..032401f 100644
--- a/Lib/idlelib/squeezer.py
+++ b/Lib/idlelib/squeezer.py
@@ -6,7 +6,7 @@
 completely unusable.
 
 This extension will automatically replace long texts with a small button.
-Double-cliking this button will remove it and insert the original text instead.
+Double-clicking this button will remove it and insert the original text instead.
 Middle-clicking will copy the text to the clipboard. Right-clicking will open
 the text in a separate viewing window.