Fix config schema

Closes #3422448

Adds the missing properties to the schema. I made a guess that cookieextra is supposed to be a string. Doesn't look like it's actually currently in use.

config/schema/http_cache_control.schema.yml

@@ -15,25 +15,38 @@ http_cache_control.settings:
               label: 'Shared max age'
             404_max_age:
               type: integer
-              label: 'Shared max age'
+              label: '404 max age'
             302_max_age:
               type: integer
-              label: 'Shared max age'
+              label: '302 max age'
             301_max_age:
               type: integer
-              label: 'Shared max age'
+              label: '301 max age'
             5xx_max_age:
               type: integer
-              label: 'Shared max age'
+              label: '5xx max age'
             stale_while_revalidate:
               type: integer
-              label: 'Shared max age'
+              label: 'Stale while revalidate'
             stale_if_error:
               type: integer
-              label: 'Shared max age'
+              label: 'Stale if error'
             vary:
               type: string
               label: 'Vary'
+            mustrevalidate:
+              type: boolean
+              label: 'Cache-Control: must-revalidate'
+            nocache:
+              type: boolean
+              label: 'Cache-Control: no-cache'
+            nostore:
+              type: boolean
+              label: 'Cache-Control: no-store'
+            cookieextra:
+              type: string
+              label: 'cookieextra'
+              nullable: true
         surrogate:
           type: mapping
           label: 'Surrogate-Control'