website: Mark architecture support pages with outdated notices

Change-Id: I9da247d73e03d83732e48f79e673a751f5fcc1b5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5-website/+/26545
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
diff --git a/_pages/documentation/general_docs/architecture_support/arm_implementation.md b/_pages/documentation/general_docs/architecture_support/arm_implementation.md
index 03cc776..8fc2e5f 100644
--- a/_pages/documentation/general_docs/architecture_support/arm_implementation.md
+++ b/_pages/documentation/general_docs/architecture_support/arm_implementation.md
@@ -8,7 +8,8 @@
 
 # ARM Implementation
 
-**Note:** The information in this page is outdated, and so are the hyperlinks.  
+{: .outdated-notice}
+The information and hyperlinks in this page may not be accurate.
 
 ## Supported features and modes
 
diff --git a/_pages/documentation/general_docs/architecture_support/index.md b/_pages/documentation/general_docs/architecture_support/index.md
index 89322d3..b06f714 100644
--- a/_pages/documentation/general_docs/architecture_support/index.md
+++ b/_pages/documentation/general_docs/architecture_support/index.md
@@ -8,7 +8,8 @@
 
 # Architecture Support
 
-**Note:** The information in this page is outdated, and so are the hyperlinks.  
+{: .outdated-notice}
+The information and hyperlinks in this page may not be accurate.
 
 ## Alpha