APM .NET library: fix link to serverless docs (#31211)

* fix link to serverless docs

* remove trailing "</strong>."

* use page title as the link

* I guess we can't do that inside alert boxes

* close the anchor tag correctly

Author: lucaspimentel

content/en/tracing/trace_collection/automatic_instrumentation/dd_libraries/dotnet-core.md

@@ -56,7 +56,7 @@ For a full list of Datadog's .NET Core library and processor architecture suppor
 ## Installation and getting started
 
 <div class="alert alert-info">
-    To set up Datadog APM in AWS Lambda, see <strong><a href="/tracing/serverless_functions/">Tracing Serverless Functions</a></strong>, in Azure App Service, see <strong><a href="/serverless/azure_app_services/">Tracing Azure App Service</a></strong>.
+    To set up Datadog APM in Serverless environments, such as AWS Lambda or Azure Functions, see <a href="/serverless">Serverless</a>.
 </div>
 
 <div class="alert alert-warning">

content/en/tracing/trace_collection/automatic_instrumentation/dd_libraries/dotnet-framework.md

@@ -60,7 +60,7 @@ For a full list of Datadog's .NET Framework library and processor architecture s
 ## Installation and getting started
 
 <div class="alert alert-info">
-  To set up Datadog APM in AWS Lambda, see <strong><a href="/tracing/serverless_functions/">Tracing Serverless Functions</a></strong>, in Azure App Service, see <strong><a href="/serverless/azure_app_services/">Tracing Azure App Service</a></strong>.
+  To set up Datadog APM in Serverless environments, such as AWS Lambda or Azure Functions, see <a href="/serverless">Serverless</a>.
 </div>
 
 <div class="alert alert-warning">