Document API ability to URL-decode resource names

All Consul HTTP API endpoints now URL-decode resource names specified in the
path, enabling resource names containing URL-invalid characters to be used
in HTTP API requests if URL-encoded into the path.

Functionality implemented in Github Pull Requests:
- #11335
- #11957
- #12103
- #12190
- #12297

Also documents CLI accepting URL-invalid resource names.

All Consul HTTP API endpoints now URL-decode resource names specified in the
path, enabling resource names containing URL-invalid characters to be used
in HTTP API requests if URL-encoded into the path. The Consul HTTP API always
supported URL-decoding of query parameters.

The CLI automatically URL-encodes arguments which are inserted as resource
names in the URL path, enabling the CLI to also interact with resource names
that contain URL-invalid characters.

website/content/api-docs/index.mdx

@@ -79,6 +79,26 @@ $ curl \
     http://127.0.0.1:8500/v1/kv/foo
 ```
 
+## URL-Encoded Resource Names
+
+Some Consul HTTP API endpoints accept resource names in URL path or query parameters.
+To pass a resource name containing URL-invalid characters, such as `/` or ` `,
+URL-encode the resource name into the URL.
+
+However, we generally recommend using resource names that don't require URL-encoding.
+Depending on the validation that Consul applies to a resource name,
+Consul may still reject a request if it considers the resource name invalid for that endpoint.
+And even if Consul considers the resource name valid, it may degrade other functionality,
+such as failed [DNS lookups](/docs/discovery/dns)
+for nodes or services with names containing invalid DNS characters.
+
+This HTTP API capability also allows the
+[CLI to accept arguments with URL-invalid characters](/commands#arguments-with-url-invalid-characters).
+
+### Invalid Characters
+
+The linefeed character (`%0a`) will cause a request to be rejected even if it is URL-encoded.
+
 ## Translated Addresses
 
 Consul 0.7 added the ability to translate addresses in HTTP response based on

website/content/commands/index.mdx

@@ -119,6 +119,12 @@ $ consul operator raft
 list-peers   remove-peer
 ```
 
+## Arguments with URL-Invalid Characters
+
+The CLI automatically URL-encodes arguments, which are then
+[URL-decoded by the underlying HTTP API endpoints](/api-docs#url-encoded-resource-names).
+To avoid double-encoding arguments, do not URL-encode arguments passed to the CLI.
+
 ## Environment Variables
 
 In addition to CLI flags, Consul reads environment variables for behavior