fixed broken links, removed Preview banner, and added further reading links to new examples doc (#28925)

Author: amymzhou

content/en/dashboards/guide/_index.md

@@ -33,7 +33,7 @@ cascade:
     {{< nextlink href="/dashboards/guide/version_history" >}}Version History{{< /nextlink >}}
     {{< nextlink href="/dashboards/guide/graphing_json/" >}}Graphing with JSON{{< /nextlink >}}
     {{< nextlink href="/dashboards/guide/using_vega_lite_in_wildcard_widgets/" >}}Using Vega-Lite with Wildcard Widgets in Datadog{{< /nextlink >}}
-    {{< nextlink href="/dashboards/guide/wildcard_examples" >}}Wildcard widget Examples{{< /nextlink >}}
+    {{< nextlink href="/dashboards/guide/wildcard_examples" >}}Wildcard Widget Examples{{< /nextlink >}}
     {{< nextlink href="/dashboards/guide/graphing_json/" >}}Graphing with JSON
     {{< /nextlink >}}
     {{< nextlink href="/dashboards/guide/tv_mode" >}}Using TV mode for Dashboards

content/en/dashboards/guide/using_vega_lite_in_wildcard_widgets.md

@@ -4,9 +4,9 @@ further_reading:
 - link: "https://docs.datadoghq.com/dashboards/widgets/wildcard/"
   tag: "Documentation"
   text: "Learn more about the Wildcard widget"
-- link: "https://docs.datadoghq.com/dashboards/guide/widget_colors/"
+- link: "https://docs.datadoghq.com/dashboards/guide/wildcard_examples"
   tag: "Documentation"
-  text: "Selecting the right colors for your graphs"
+  text: "Wildcard Widget Examples"
 - link: "https://docs.datadoghq.com/dashboards/guide/context-links/#context-links-variables"
   tag: "Documentation"
   text: "Using Context Links in Dashboards"

content/en/dashboards/guide/wildcard_examples.md

@@ -1,7 +1,7 @@
 ---
 title: Wildcard Widget Examples
 further_reading:
-- link: "/dashboards/wildcard_widget"
+- link: "/dashboards/widgets/wildcard"
   tag: "Documentation"
   text: "Learn more about the Wildcard widget"
 - link: "/dashboards/guide/using_vega_lite_in_wildcard_widgets"

content/en/dashboards/widgets/wildcard.md

@@ -5,18 +5,14 @@ further_reading:
 - link: "/dashboards/guide/using_vega_lite_in_wildcard_widgets/"
   tag: "Documentation"
   text: "Learn more about using Vega-Lite with Wildcard widgets"
+- link: "https://docs.datadoghq.com/dashboards/guide/wildcard_examples"
+  tag: "Documentation"
+  text: "Wildcard Widget Examples"
 - link: "https://vega.github.io/vega-lite/tutorials/getting_started.html"
   tag: "Vega Tutorial"
   text: "Introduction to Vega-Lite"
-- link: "https://vega.github.io/vega-lite/tutorials/explore.html"
-  tag: "Vega Tutorial"
-  text: "Exploring Data"
 ---
 
-{{< callout url="https://forms.gle/tLdC1AqhVizD3wCp7" btn_hidden="false" header="Access the Preview!">}}
-Wildcard widgets are in Preview. Sign up for access!
-{{< /callout >}}
-
 ## Overview
 
 The Wildcard widget in Datadog extends the flexibility of the [open-source Vega-Lite][1] "Grammar of Graphics" language, and integrates it with the Datadog platform. The Wildcard widget allows you to create graphs that are not available within native Datadog widgets and query systems.