restoring some of the original default content

Author: inventarSarah

docs/platforms/javascript/common/index.mdx

@@ -1,3 +1,5 @@
+<PlatformContent includePath="getting-started-primer" />
+
 <PlatformSection noGuides>
 
 <PlatformContent includePath="llm-rules-platform" />
@@ -36,10 +38,18 @@ Select which Sentry features you'd like to install in addition to Error Monitori
 
 </PlatformSection>
 
+<PlatformSection supported={["javascript.nextjs"]}>
+
 ## Step 1: Install
 
+</PlatformSection>
+
+<PlatformSection notSupported={["javascript.nextjs"]}>
+  ## Step 1: Install
+</PlatformSection>
+
 <PlatformCategorySection notSupported={["server"]}>
-  <PlatformSection notSupported={["javascript"]}>
+  <PlatformSection notSupported={["javascript", "javascript.cordova"]}>
     <OnboardingOptionButtons
       options={[
         "error-monitoring",