`MissingPreposition` triggered wrongly for "However, explorer does more work that just icon layout."

> However, explorer does more work that just icon layout. If some of its tasks are O(n) – linear – then they will diffuse the impact of the O(n^2) tasks. As ‘n’ increases the O(n^2) tasks will eventually dominate, but I didn’t want my test harness to run even longer than the 160 seconds it was already taking.

This is true with a build of HEAD post version 2.10.0

Start by locating the MissingPreposition rule and reproduce the warning on the quoted sentence using a current HEAD build. Trace why "that just" is flagged, then add a regression test for this text and confirm the warning no longer appears while the intended preposition cases remain covered.

Written by the indexing model from the issue text.