Make all image string templates code formatted.

Update our docs to code format all the image template strings that a
disk can use.

website/source/docs/providers/google/r/compute_disk.html.markdown

@@ -38,10 +38,10 @@ The following arguments are supported:
     to encrypt this disk.
 
 * `image` - (Optional) The image from which to initialize this disk. This can be
-    one of: the image self_link, projects/{project}/global/images/{image},
-    projects/{project}/global/images/family/{family}, global/images/{image},
-    global/images/family/{family}, family/{family}, {project}/{family},
-    {project}/{image}, {family}, or {image}.
+    one of: the image's `self_link`, `projects/{project}/global/images/{image}`,
+    `projects/{project}/global/images/family/{family}`, `global/images/{image}`,
+    `global/images/family/{family}`, `family/{family}`, `{project}/{family}`,
+    `{project}/{image}`, `{family}`, or `{image}`.
 
 * `project` - (Optional) The project in which the resource belongs. If it
     is not provided, the provider project is used.

website/source/docs/providers/google/r/compute_instance.html.markdown

@@ -118,10 +118,10 @@ the type is "local-ssd", in which case scratch must be true).
     `google_compute_disk`) to attach.
 
 * `image` - The image from which to initialize this disk. This can be
-    one of: the image self_link, projects/{project}/global/images/{image},
-    projects/{project}/global/images/family/{family}, global/images/{image},
-    global/images/family/{family}, family/{family}, {project}/{family},
-    {project}/{image}, {family}, or {image}.
+    one of: the image's `self_link`, `projects/{project}/global/images/{image}`,
+    `projects/{project}/global/images/family/{family}`, `global/images/{image}`,
+    `global/images/family/{family}`, `family/{family}`, `{project}/{family}`,
+    `{project}/{image}`, `{family}`, or `{image}`.
 
 * `auto_delete` - (Optional) Whether or not the disk should be auto-deleted.
     This defaults to true. Leave true for local SSDs.

website/source/docs/providers/google/r/compute_instance_template.html.markdown

@@ -177,11 +177,11 @@ The `disk` block supports:
     to the name of the instance.
 
 * `source_image` - (Required if source not set) The image from which to
-    initialize this disk. This can be one of: the image self_link,
-    projects/{project}/global/images/{image},
-    projects/{project}/global/images/family/{family}, global/images/{image},
-    global/images/family/{family}, family/{family}, {project}/{family},
-    {project}/{image}, {family}, or {image}.
+    initialize this disk. This can be one of: the image's `self_link`,
+    `projects/{project}/global/images/{image}`,
+    `projects/{project}/global/images/family/{family}`, `global/images/{image}`,
+    `global/images/family/{family}`, `family/{family}`, `{project}/{family}`,
+    `{project}/{image}`, `{family}`, or `{image}`.
 
 * `interface` - (Optional) Specifies the disk interface to use for attaching
     this disk.