Go-specific ALTS authentication page from template (#537)

- Contributes to #527
- Also included are minor tweaks to the C++-ALTS page

content/docs/guides/auth/ALTS.md

@@ -27,7 +27,10 @@ protocol with few lines of code. gRPC ALTS is supported in C++, Java, Go, and
 Python.
 
 Details are covered in this page, or in the following language-specific
-page: [C++ ALTS]({{< relref "docs/languages/cpp/alts" >}}).
+pages:
+
+- [ALTS in C++]({{< relref "docs/languages/cpp/alts" >}})
+- [ALTS in Go]({{< relref "docs/languages/go/alts" >}})
 
 Note that ALTS is fully functional if the application runs on
 [Google Cloud Platform](https://cloud.google.com). ALTS could be run on any
@@ -49,18 +52,6 @@ ManagedChannel managedChannel =
     AltsChannelBuilder.forTarget(serverAddress).build();
 ```
 
-#### Go
-
-```go
-import (
-  "google.golang.org/grpc"
-  "google.golang.org/grpc/credentials/alts"
-)
-
-altsTC := alts.NewClientCreds(alts.DefaultClientOptions())
-conn, err := grpc.Dial(serverAddr, grpc.WithTransportCredentials(altsTC))
-```
-
 #### Python
 
 ```python
@@ -87,18 +78,6 @@ Server server = AltsServerBuilder.forPort(<port>)
 
 ```
 
-#### Go
-
-```go
-import (
-  "google.golang.org/grpc"
-  "google.golang.org/grpc/credentials/alts"
-)
-
-altsTC := alts.NewServerCreds(alts.DefaultServerOptions())
-server := grpc.NewServer(grpc.Creds(altsTC))
-```
-
 #### Python
 
 ```python
@@ -130,20 +109,6 @@ ManagedChannel channel =
          .build();
 ```
 
-#### Go
-
-```go
-import (
-  "google.golang.org/grpc"
-  "google.golang.org/grpc/credentials/alts"
-)
-
-clientOpts := alts.DefaultClientOptions()
-clientOpts.TargetServiceAccounts = []string{expectedServerSA}
-altsTC := alts.NewClientCreds(clientOpts)
-conn, err := grpc.Dial(serverAddr, grpc.WithTransportCredentials(altsTC))
-```
-
 ### Client Authorization
 
 On a successful connection, the peer information (e.g., client’s service
@@ -165,14 +130,3 @@ ServerCall<?, ?> call;
 Status status = AuthorizationUtil.clientAuthorizationCheck(
     call, Lists.newArrayList("foo@iam.gserviceaccount.com"));
 ```
-
-#### Go
-
-```go
-import (
-  "google.golang.org/grpc"
-  "google.golang.org/grpc/credentials/alts"
-)
-
-err := alts.ClientAuthorizationCheck(ctx, []string{"foo@iam.gserviceaccount.com"})
-```

content/docs/languages/cpp/alts.md

@@ -1,10 +1,11 @@
 ---
-title: ALTS authentication
+title: ALTS authentication in C++
 short: ALTS
 layout: auth_alts
 description: >
   An overview of gRPC authentication in C++ using Application Layer Transport
   Security (ALTS).
+weight: 75
 spelling: cSpell:ignore Authz creds grpcpp
 code:
   client_credentials: |

content/docs/languages/go/_index.md

@@ -4,9 +4,9 @@ layout: prog_lang_home
 api_path: https://pkg.go.dev/google.golang.org/grpc
 content:
   - learn_more:
-    - "[Examples]($src_repo_url/tree/master/examples)"
+    - "[ALTS authentication](alts/)"
     - "[Additional docs]($src_repo_url/tree/master/Documentation)"
-    - "[Installation]($src_repo_url#installation)"
+    - "[Examples]($src_repo_url/tree/master/examples)"
     - "[FAQ]($src_repo_url#faq)"
   - reference:
     - "[API](api/)"
@@ -14,6 +14,7 @@ content:
   - other:
     - $src_repo_link
     - "[Performance benchmark](https://performance-dot-grpc-testing.appspot.com/explore?dashboard=5652536396611584&widget=490377658&container=1286539696)"
+    - "[Installation]($src_repo_url#installation)"
 spelling: cSpell:ignore Isberner Klerk Malte youtube
 ---
 

content/docs/languages/go/alts.md

@@ -0,0 +1,52 @@
+---
+title: ALTS authentication in Go
+short: ALTS
+layout: auth_alts
+description: >
+  An overview of gRPC authentication in Go using Application Layer Transport
+  Security (ALTS).
+weight: 75
+spelling: cSpell:ignore creds
+code:
+  client_credentials: |
+    ```go
+    import (
+      "google.golang.org/grpc"
+      "google.golang.org/grpc/credentials/alts"
+    )
+
+    altsTC := alts.NewClientCreds(alts.DefaultClientOptions())
+    conn, err := grpc.Dial(serverAddr, grpc.WithTransportCredentials(altsTC))
+    ```
+  server_credentials: |
+    ```go
+    import (
+      "google.golang.org/grpc"
+      "google.golang.org/grpc/credentials/alts"
+    )
+
+    altsTC := alts.NewServerCreds(alts.DefaultServerOptions())
+    server := grpc.NewServer(grpc.Creds(altsTC))
+    ```
+  server_authorization: |
+    ```go
+    import (
+      "google.golang.org/grpc"
+      "google.golang.org/grpc/credentials/alts"
+    )
+
+    clientOpts := alts.DefaultClientOptions()
+    clientOpts.TargetServiceAccounts = []string{expectedServerSA}
+    altsTC := alts.NewClientCreds(clientOpts)
+    conn, err := grpc.Dial(serverAddr, grpc.WithTransportCredentials(altsTC))
+    ```
+  client_authorization: |
+    ```go
+    import (
+      "google.golang.org/grpc"
+      "google.golang.org/grpc/credentials/alts"
+    )
+
+    err := alts.ClientAuthorizationCheck(ctx, []string{"foo@iam.gserviceaccount.com"})
+    ```
+---