Fix cdn swagger api description issue (Azure#19023)

* Add blockchain to latest profile

* Add additional types

* Fix api description issues

Co-authored-by: Mark Cowlishaw <markcowl@microsoft.com>
Co-authored-by: Chenglong Liu <chengll@microsoft.com>

Author: 3 people

specification/cdn/resource-manager/Microsoft.Cdn/stable/2021-06-01/afdx.json

@@ -87,7 +87,7 @@
         "tags": [
           "AFDProfiles"
         ],
-        "description": "Checks the quota and actual usage of endpoints under the given CDN profile.",
+        "description": "Checks the quota and actual usage of AzureFrontDoor endpoints under the given CDN profile.",
         "operationId": "AFDProfiles_ListResourceUsage",
         "x-ms-examples": {
           "AFDProfiles_ListResourceUsage": {
@@ -136,7 +136,7 @@
         "tags": [
           "AFDProfiles"
         ],
-        "description": "Validates the custom domain mapping to ensure it maps to the correct CDN endpoint in DNS.",
+        "description": "Check the name availability of a host name.",
         "operationId": "AFDProfiles_CheckHostNameAvailability",
         "x-ms-examples": {
           "AFDProfiles_CheckHostNameAvailability": {
@@ -926,7 +926,7 @@
         "tags": [
           "AFDEndpoints"
         ],
-        "description": "Checks the quota and actual usage of endpoints under the given CDN profile.",
+        "description": "Checks the quota and actual usage of the given AzureFrontDoor endpoint under the given CDN profile.",
         "operationId": "AFDEndpoints_ListResourceUsage",
         "x-ms-examples": {
           "AFDEndpoints_ListResourceUsage": {
@@ -982,7 +982,7 @@
         "tags": [
           "AFDEndpoints"
         ],
-        "description": "Validates the custom domain mapping to ensure it maps to the correct CDN endpoint in DNS.",
+        "description": "Validates the custom domain mapping to ensure it maps to the correct CDN endpoint in DNS.This api isn't work for apex domain.",
         "operationId": "AFDEndpoints_ValidateCustomDomain",
         "x-ms-examples": {
           "Endpoints_ValidateCustomDomain": {
@@ -1350,7 +1350,7 @@
         "tags": [
           "AFDOriginGroups"
         ],
-        "description": "Checks the quota and actual usage of endpoints under the given CDN profile.",
+        "description": "Checks the quota and actual usage of the given AzureFrontDoor origin group under the given CDN profile.",
         "operationId": "AFDOriginGroups_ListResourceUsage",
         "x-ms-examples": {
           "AFDOriginGroups_ListResourceUsage": {
@@ -2305,7 +2305,7 @@
         "tags": [
           "RuleSets"
         ],
-        "description": "Checks the quota and actual usage of endpoints under the given CDN profile.",
+        "description": "Checks the quota and actual usage of the given AzureFrontDoor rule set under the given CDN profile.",
         "operationId": "RuleSets_ListResourceUsage",
         "x-ms-examples": {
           "RuleSets_ListResourceUsage": {