Add rstrip() to the Format menu.

Python's svn repository no longer accepts files with trailing whitespace
and it is often necessary to run reindent.py before submitting.  It
would be nice to have this as a built-in formatting tool.

If the interactive interpreter did not require blank lines within blocks
to have at least one 'trailing' space to avoid prematurely ending the
block (as when copy from editor window and paste), IDLE could
automatically rstrip lines.  Given that that should not be done, a menu
item would be nice.

Here's an extension that adds rstrip() to the Format menu.

Applied in r72999.  Will backport to 2.7.

Backported in r73001

This has been closed but why not promote reindent.py to a module and add
an option on IDLE to allow a complete reindent.py run ?