Fix some html errors (refs #46 #51)

- Fix duplicate main_navbar id on top page.
- Fix missing ';' in nbsp entity in footer.
- Fix nested <a> tags in checkpoint/restore doc.
- Fix nested <p> tags on top page feature blocks.
- Add '--check-html' option to htmlproofer build step.

cloudbuild.yaml

@@ -18,7 +18,7 @@ steps:
     args: ["make"]
   # Test the HTML for issues.
   - name: 'gcr.io/gvisor-website/html-proofer:3.10.2'
-    args: ["htmlproofer", "--disable-external", "public/static"]
+    args: ["htmlproofer", "--disable-external", "--check-html", "public/static"]
   # Deploy to App Engine only for master branch.
   - name: 'gcr.io/cloud-builders/gcloud'
     entrypoint: 'bash'

content/_index.html

@@ -20,32 +20,32 @@ gVisor integrates with <a href="https://www.docker.com/" target="_blank" rel="no
 
 {{< blocks/section color="dark" >}}
 
-{{% blocks/feature icon="fas fa-lock" title="Defense in Depth" %}}
+{{< blocks/feature icon="fas fa-lock" title="Defense in Depth" >}}
 Each sandbox has its own user-space kernel, providing additional protection from host kernel vulnerabilities.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
-{{% blocks/feature icon="fas fa-feather-alt" title="Lightweight" %}}
+{{< blocks/feature icon="fas fa-feather-alt" title="Lightweight" >}}
 Runs as a normal process and uses the host kernel for memory management and scheduling.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
-{{% blocks/feature icon="fab fa-linux" title="Zero Configuration" %}}
+{{< blocks/feature icon="fab fa-linux" title="Zero Configuration" >}}
 Capable of running most Linux applications unmodified, with zero configuration.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
 {{< /blocks/section >}}
 
 {{< blocks/section color="white" >}}
 
-{{% blocks/feature icon="fas fa-book" title="Read the Docs" %}}
+{{< blocks/feature icon="fas fa-book" title="Read the Docs" >}}
 Read the [documentation](./docs/) to understand gVisor, its architecture and trade-offs, and how to use it.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
-{{% blocks/feature icon="fas fa-code-branch" title="Contribute to gVisor" %}}
+{{< blocks/feature icon="fas fa-code-branch" title="Contribute to gVisor" >}}
 Anyone is welcome to be a gVisor contributor. Please check out the [community information](./docs/community) to get started.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
-{{% blocks/feature icon="fab fa-github" title="Give Feedback" %}}
+{{< blocks/feature icon="fab fa-github" title="Give Feedback" >}}
 File feature requests, bugs, and compatibility issues on <a href="https://github.com/google/gvisor/issues" target="_blank" rel="noopener">GitHub</a>.
-{{% /blocks/feature %}}
+{{< /blocks/feature >}}
 
 {{< /blocks/section >}}

content/docs/user_guide/checkpoint_restore.md

@@ -83,25 +83,19 @@ docker start --checkpoint --checkpoint-dir=<directory> <container>
 
 ### Issues Preventing Compatibility with Docker
 
-#### [Moby #37360][leave-running]
-
-Docker version 18.03.0-ce and earlier hangs when checkpointing and does not
-create the checkpoint. To successfully use this feature, install a custom
-version of docker-ce from the moby repository. This issue is caused by an
-improper implementation of the `--leave-running` flag. This issue is fixed in
-newer releases.
-
-#### Docker does not support restoration into new containers.
-
-Docker currently expects the container which created the checkpoint to be the
-same container used to restore which is not possible in runsc. When Docker
-supports container migration and therefore restoration into new containers, this
-will be the flow.
-
-#### [Moby #37344][checkpoint-dir]
-
-Docker does not currently support the `--checkpoint-dir` flag but this will be
-required when restoring from a checkpoint made in another container.
+- **[Moby #37360][leave-running]:** Docker version 18.03.0-ce and earlier hangs
+  when checkpointing and does not create the checkpoint. To successfully use
+  this feature, install a custom version of docker-ce from the moby repository.
+  This issue is caused by an improper implementation of the `--leave-running`
+  flag. This issue is fixed in newer releases.
+- **Docker does not support restoration into new containers:** Docker currently
+  expects the container which created the checkpoint to be the same container
+  used to restore which is not possible in runsc. When Docker supports container
+  migration and therefore restoration into new containers, this will be the
+  flow.
+- **[Moby #37344][checkpoint-dir]:** Docker does not currently support the
+  `--checkpoint-dir` flag but this will be required when restoring from a
+  checkpoint made in another container.
 
 [leave-running]: https://github.com/moby/moby/pull/37360
 [checkpoint-dir]: https://github.com/moby/moby/issues/37344

layouts/partials/footer.html

@@ -15,7 +15,7 @@
         <ul class="list-inline mb-0">
           {{ template "footer-links-block"  . }}
           {{ end }}
-          <li class="list-inline-item mx-2" >&nbsp</li>
+          <li class="list-inline-item mx-2" >&nbsp;</li>
           <li class="list-inline-item mx-2" >
             <img src="/img/powered-gvisor.png" alt="Powered by gVisor">
           </li>

layouts/shortcodes/blocks/cover.html

@@ -27,7 +27,7 @@
     <div class="row">
       <div class="cover-content col-12">
         <nav class="navbar navbar-expand navbar-dark flex-column flex-md-row">
-          <div class="td-navbar-nav-scroll ml-md-auto" id="main_navbar">
+          <div class="td-navbar-nav-scroll ml-md-auto" id="cover_navbar">
             <ul class="navbar-nav mt-2 mt-lg-0">
               {{ $p := . }}
               {{ range .Site.Menus.main }}