[19.7] Update release note for #18127

[twstokes]

This PR updates the release note for the changes submitted by an external contributor in #18127.

Originally the issue seemed limited to Reader, but the final fix affected multiple areas of the app that render web previews.

[wpmobilebot]

You can test the changes in Jetpack from this Pull Request by:

• Clicking here or scanning the QR code below
• Then installing the build number pr18401-62018c4 from App Center on your iPhone

The .ipa file can also be downloaded directly here.
If you need access to App Center, please ask a maintainer to add you.

[wpmobilebot]

You can test the changes in WordPress from this Pull Request by:

• Clicking here or scanning the QR code below
• Then installing the build number pr18401-62018c4 from App Center on your iPhone

The .ipa file can also be downloaded directly here.
If you need access to App Center, please ask a maintainer to add you.

[peril-wordpress-mobile]

	Warnings
⚠️	PR is missing at least one label.
⚠️	This PR contains changes to RELEASE_NOTES.txt. Note that these changes won't affect the final version of the release notes as this version is in code freeze. Please, get in touch with a release manager if you want to update the final release notes.

Generated by 🚫 dangerJS

[twstokes]

👋 @mokagio - I helped with this external contribution and didn't think to tweak the release notes until now. Could you let me know if this will be a big problem and how we should proceed? Apologies for throwing a 🔧 in things.

[mokagio]

👍

[mokagio]

@twstokes

👋 @mokagio - I helped with this external contribution and didn't think to tweak the release notes until now. Could you let me know if this will be a big problem and how we should proceed? Apologies for throwing a 🔧 in things.

No worries at all. I'll merge the PR now and make sure the notes including this tweak reach our copy writer. Easy peasy.