feat(apple): Add docs for enableSigterm (#10216)

Add docs for the new enableSigterm options available on Sentry Cocoa
8.27.0 and above.

Co-authored-by: vivianyentran <20403606+vivianyentran@users.noreply.github.com>

Author: philipphofmann

docs/platforms/apple/common/configuration/options.mdx

@@ -87,6 +87,17 @@ This option is turned on by default.
 
 Grouping in Sentry is different for events with stack traces and without. As a result, you will get new groups as you enable or disable this flag for certain events.
 
+</ConfigKey>
+
+<ConfigKey name="enable-sigterm-reporting">
+
+_(New in [sentry-cocoa version 8.27.0](https://github.com/getsentry/sentry-cocoa/blob/main/CHANGELOG.md#8270))_
+
+When enabled, the SDK reports SIGTERM signals to Sentry.
+
+It's crucial for developers to understand that the OS sends a SIGTERM to their app as a prelude to a graceful shutdown, before resorting to a SIGKILL. This SIGKILL, which your app can't catch or ignore, is a direct order to terminate your app's process immediately. Developers should be aware that their app can receive a SIGTERM in various scenarios, such as  CPU or disk overuse, watchdog terminations, or when the OS updates your app.
+
+
 </ConfigKey>
 
 <ConfigKey name="send-default-pii">