doc/go1.25: document macOS requirements

For #69839.
For #71661.

Change-Id: Ic13f4b7fb81461d55216b260384ee10037b86054
Reviewed-on: https://go-review.googlesource.com/c/go/+/663515
TryBot-Bypass: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: cagedmantis

doc/next/7-ports.md

@@ -1,5 +1,10 @@
 ## Ports {#ports}
 
+### Darwin
+
+<!-- go.dev/issue/69839 -->
+As [announced](/doc/go1.24#darwin) in the Go 1.24 release notes, Go 1.25 requires macOS 12 Monterey or later; support for previous versions has been discontinued.
+
 ### Windows
 
 <!-- go.dev/issue/71671 -->