add desc to schema for 3 compute resources (#3680) (#2220)

Co-authored-by: Edward Sun <[email protected]>
Signed-off-by: Modular Magician <[email protected]>

Co-authored-by: Edward Sun <[email protected]>

Author: modular-magician

.changelog/3680.txt

@@ -0,0 +1,3 @@
+```release-note:none
+
+```

google-beta/resource_compute_instance_from_template.go

@@ -68,9 +68,10 @@ func computeInstanceFromTemplateSchema() map[string]*schema.Schema {
 	})
 
 	s["source_instance_template"] = &schema.Schema{
-		Type:     schema.TypeString,
-		Required: true,
-		ForceNew: true,
+		Type:        schema.TypeString,
+		Required:    true,
+		ForceNew:    true,
+		Description: `Name or self link of an instance template to create the instance based on.`,
 	}
 
 	return s

google-beta/resource_compute_project_default_network_tier.go

@@ -31,14 +31,16 @@ func resourceComputeProjectDefaultNetworkTier() *schema.Resource {
 			"network_tier": {
 				Type:         schema.TypeString,
 				Required:     true,
+				Description:  `The default network tier to be configured for the project. This field can take the following values: PREMIUM or STANDARD.`,
 				ValidateFunc: validation.StringInSlice([]string{"PREMIUM", "STANDARD"}, false),
 			},
 
 			"project": {
-				Type:     schema.TypeString,
-				Optional: true,
-				Computed: true,
-				ForceNew: true,
+				Type:        schema.TypeString,
+				Optional:    true,
+				Computed:    true,
+				ForceNew:    true,
+				Description: `The ID of the project in which the resource belongs. If it is not provided, the provider project is used.`,
 			},
 		},
 	}

google-beta/resource_compute_project_metadata_item.go

@@ -28,19 +28,22 @@ func resourceComputeProjectMetadataItem() *schema.Resource {
 
 		Schema: map[string]*schema.Schema{
 			"key": {
-				Type:     schema.TypeString,
-				Required: true,
-				ForceNew: true,
+				Type:        schema.TypeString,
+				Required:    true,
+				ForceNew:    true,
+				Description: `The metadata key to set.`,
 			},
 			"value": {
-				Type:     schema.TypeString,
-				Required: true,
+				Type:        schema.TypeString,
+				Required:    true,
+				Description: `The value to set for the given metadata key.`,
 			},
 			"project": {
-				Type:     schema.TypeString,
-				Optional: true,
-				Computed: true,
-				ForceNew: true,
+				Type:        schema.TypeString,
+				Optional:    true,
+				Computed:    true,
+				ForceNew:    true,
+				Description: `The ID of the project in which the resource belongs. If it is not provided, the provider project is used.`,
 			},
 		},