Escape html find replace

[nicksc]

🛑 Only PRs related to localization are being accepted for Twine 2.4 right now.
🛑 Only PRs that fix bugs will be accepted for Twine 2.3. No PRs that add new features or modify existing functionality will be accepted.

Description

Fixed visual issue where HTML code isn't displayed correctly in the Find/Replace preview box. Before Fix: After Fix:
There are two limitations with this fix: if the user enters "&amp" it will be displayed as "&" in the preview box and if the user enters both "<"/">" and "&lt"/"&gt" only the HTML will be escaped. However, the encountering of these two limitations are unlikely and we believe the additional functionality outweighs these limitations.

Issues fixed

https://github.com/klembot/twinejs/issues/1104

Credit

Please put an X in one of the squares below only.

[X] I would like to be credited in the application as: Nicholas Chung, Saksham Gurung, and Tamara Andrade
[ ] I would not like my name to appear in the application credits.

Presubmission checklist

Put an X in the squares below to indicate you've done each step.

[X] I have read this project's CONTRIBUTING file and this PR follows the criteria laid out there.
[X] This contribution was created by me and I have the right to submit it under the GPL v3 license. (This is not a rights assignment.)
[X] I have read and agree to abide by this project's Code of Conduct.

[nicksc]

@klembot hello! Saksham Gurung, Tamara Andrade (mentor), and I worked on this bug fix as a part of our time at CodeDay Labs [https://labs.codeday.org/]. However, It doesn't seem like I have the necessary permissions to add you as a reviewer. Wanted to flag this PR to you as the code owner. Thank you.

[klembot]

Hi, I'm really sorry for letting this PR sit so long. I believe this issue was fixed as of version 2.4, but if that's not the case, please let me know.