Update documentation for Xcode 26.1 image (#9740)

We've replaced Xcode 26.1 RC with 26.1. This change updates links and information to reflect the new image.

Author: OompahLoompah

docs/guides/modules/ROOT/partials/execution-resources/xcode-silicon-vm.adoc

@@ -8,12 +8,12 @@
 | Release Notes
 
 | `26.1.0`
-| Xcode 26.1 RC (17B54)
+| Xcode 26.1 (17B55)
 | 15.6
 a| `m4pro.medium` +
    `m4pro.large`
-| link:https://circle-macos-docs.s3.amazonaws.com/image-manifest/v15780/manifest.txt[Installed software]
-| link:https://circleci.com/changelog/xcode-26-1-rc-available/[Release Notes]
+| link:https://circle-macos-docs.s3.amazonaws.com/image-manifest/v15804/manifest.txt[Installed software]
+| link:https://circleci.com/changelog/xcode-26-1-available/[Release Notes]
 
 | `26.0.1`
 | Xcode 26.0.1 (17A400)