cli: fix typo in help text for 'consul acl role read' (hashicorp#5311)

Author: rboyer

command/acl/policy/read/policy_read.go

@@ -89,14 +89,14 @@ const help = `
 Usage: consul acl policy read [options] POLICY
 
     This command will retrieve and print out the details
-    of a single policy
+    of a single policy.
 
     Read:
 
-        $ consul acl policy read fdabbcb5-9de5-4b1a-961f-77214ae88cba
+        $ consul acl policy read -id fdabbcb5-9de5-4b1a-961f-77214ae88cba
 
     Read by name:
 
-        $ consul acl policy read -by-name my-policy
+        $ consul acl policy read -name my-policy
 
 `