BUG REPORT: gitk displays diffs with angle brackets incorrectly

Summary: Certain diffs containing angle brackets ('<' or '>' characters) are displayed incorrectly in gitk's "markup words" and "color words" modes. The bug is caused by a feature that isn't aware of the formatting difference for the word diff modes.

How to reproduce the bug:
 
Create a file with the following, and commit:
x < 1
y > 2
 
Modify it to this, and commit:
z < 1
w > 2
 
Then view the results with:
gitk --color-words
 
You will see:
 * "Diff" shows bogus removal on 1st line and bogus addition on 2nd line.
 * "Old version" cuts off at right angle bracket.
 * "New Version" cuts off at left angle bracket.

I personally use a 2-line patch to fix this by disabling/breaking the feature that does string comparisons for "  >" and "  <", but I know that's not the correct fix, so I'm not including it in this post.