Headify the subsections.

docs/static/upgrading.asciidoc

@@ -70,14 +70,14 @@ For a comprehensive understanding of how to handle such scenarios and ensure com
 <<plugins-filters-elastic_integration,elastic_integration filter>> plugin requires a special attention due to its dependencies on various components of the stack such as {es}, {kib} and {ls}.
 Any updates, deprecations, or changes in the stack products can directly impact the functionality of the plugin.
 
-* when upgrading {es}
+*When upgrading {es}*
 
 This plugin is compiled with a specific version of {es} and embeds {es} Ingest Node components that match the `major.minor` stack version. Therefore, we recommend using a plugin version that aligns with the `major.minor` version of your stack.
 
 If the versions do not match, the plugin may encounter issues such as failing to load or execute pipelines. For example, if your {es} version is newer than the plugin, the plugin may not support new features introduced in the updated {es} version.
 Conversely, if your {es} version is older, the plugin may rely on features that have been deprecated or removed in your {es} version.
 
-* when upgrading {kib}
+*When upgrading {kib}*
 
 When you upgrade {kib}, {kib} downloads the latest version of the integrations through {fleet-guide}/fleet-overview.html#package-registry-intro[Elastic Package Registry].
 As part of the upgrade process, you will also have the opportunity to review and upgrade your currently installed integrations to their latest versions.
@@ -86,7 +86,7 @@ This is because <<plugins-filters-elastic_integration,elastic_integration filter
 These pipelines are then executed using the {es} Ingest Node components that the plugin was compiled with.
 If {es} or {es} is upgraded first, there is a risk of incompatibility between the plugin's ingest componenets and the newer versions of {es}'s Ingest Node features or {kib}'s integration definitions.
 
-* when upgrading {ls}
+*When upgrading {ls}*
 
 This plugin is by default embedded in {ls} core. When you upgrade {ls}, new version of the plugin is installed.
 The plugin is backward compatible accross {ls} 8.x versions. However, if you are considering to upgrade {ls} only (not the plugin), there are exceptions cases, such as JDK compatibility which require matching certain {ls} versions.