Improve collection patterns in script templates

[marceltaeumel]

This snippet yields the wrong script:

[:morph | morph submorphs sorted: [:a :b | a topLeft < b topLeft ]]

...because the current detection just looks for #sorted: (among others), while ignoring the sender. However, only messages send to :morph are relevant here. (I think there is still no need to consider renaming via temporary variables etc.)