The hot key SHIFT + CTRL + C invokes the Package template, it's not really an auto complete. The Template gives both a function and package template for you to work off of. Just remove any part of the template you are not using.
Per the Toad Help File: (Press F1 and then do a search for "Using Templates within Packages")
1. In the Editor, load a package spec or create a new one.
2. Enter a new declaration for a package procedure or function into the spec.
Press Ctrl+Shift+C. The default package procedure or package function template is used to create a new procedure in the package body.