Reassign Debug Launch shortcut to Alt + F9

Summary:
The was a key shortcut conflict between KatePart and KDevelop for the F9 key.
Easily fixed by reassigning Debug Launch to Alt + F9.

BUG: 386918
FIXED-IN: 5.3.0

Reviewers: #kdevelop, kdevelop-devel, brauch

Reviewed By: #kdevelop, brauch

Subscribers: brauch, kdevelop-devel, #kdevelop

Tags: #kdevelop

Differential Revision: https://phabricator.kde.org/D11431