Show variable on first mention in display

[colin-grant-work]

What it does

Fixes an issue where a variable's name would not be shown if it started before the current display start.

How to test

1. Load some memory that includes a variable with a large memory footprint.
2. Set the display parameters such that the variable starts before the initial address but continues into the frame.
3. The variable's name should still be displayed.
4. All variable's names should be displayed exactly once.

Review checklist

• [x] as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines