New EOL message for Tor Browser 13.5.

Strings from tpo/applications/tor-browser!1217 (merged), which has not landed yet, but the strings shouldn't change.

NOTE: even though it says "Will be unused in Tor Browser 14.0!" this is actually high priority for translation since the build that uses them is next week. @emmapeel from what I remember, you added a rule to weblate to de-prioritise messages with this comment. Can you override it to give this normal or high priority instead?

Also added a screenshots for each string.

en-US/tor-browser.ftl

@@ -729,3 +729,16 @@ yec-2024-close-button =
 downloads-tor-warning-title = Be careful opening downloads
 # "Tails" is the brand name for the Tails operating system and should be localized appropriately, and will be a link to its website. The name should be wrapped in '<a data-l10n-name="tails-link">' and '</a>'.
 downloads-tor-warning-description = Some files may connect to the internet when opened without using Tor. To be safe, open the files while offline or use a portable operating system like <a data-l10n-name="tails-link">Tails</a>.
+
+## Will be unused in Tor Browser 14.0!
+## Notification for dropped operating system support.
+
+# "{ -brand-short-name }" will be replaced with the localized name of the browser, e.g. "Tor Browser".
+# "13.5" refers to the browser version number.
+# "macOS" is a brand name, and 10.15 is the macOS version number.
+dropped-support-notification-macos-version-less-than-10-15-extended-13-5 = { -brand-short-name } 13.5 will only receive security updates for a limited time. Please upgrade to macOS 10.15 or later to receive the latest version of { -brand-short-name }.
+
+# "{ -brand-short-name }" will be replaced with the localized name of the browser, e.g. "Tor Browser".
+# "13.5" refers to the browser version number.
+# "Windows" is a brand name, and "Windows 10" is the version.
+dropped-support-notification-win-os-version-less-than-10-extended-13-5 = { -brand-short-name } 13.5 will only receive security updates for a limited time. Please upgrade to Windows 10 or later to receive the latest version of { -brand-short-name }.