Add WIP cache docs

v2:-Documentation.md

@@ -80,6 +80,7 @@ This page describes how to use Caddy 2, which is a work-in-progress on the [v2 b
 				- [http.matchers.file](#httpmatchersfile)
 			- [http/servers/handle](#httpservershandle)
 				- Middleware (non-terminating handlers):
+					- [http.handlers.cache](#httphandlerscache)
 					- [http.handlers.headers](#httphandlersheaders)
 					- [http.handlers.rewrite](#httphandlersrewrite)
 					- [http.handlers.markdown](#httphandlersmarkdown)
@@ -1202,7 +1203,7 @@ A map of server ID (of your choice) to its configuration object. Each server is
 - `max_rehandles`: How many rehandles to allow; prevents infinite looping.
 - `strict_sni_host`: If true, enforce that an HTTP Host header matches the connection's ServerName (SNI) value from the TLS handshake. Important when using TLS client authentication.
 - `experimental_http3`: If true, IETF-draft-compliant HTTP/3 ("QUIC") will be enabled. It creates a UDP listener. This feature is experimental and is not subject to compatibility promises.
-- `logs`: Enables and configures HTTP access and error logging. An empty object uses default settings. Access logs document HTTP requests as they come in; they use the namespace `http.log.access`. Error logs record HTTP handler errors and use the namespace `http.log.error`.
+- `logs`: Enables and configures HTTP access logging. An empty object uses default settings. Access logs document HTTP requests as they come in; they use the namespace `http.log.access`. Error logs record HTTP handler errors and use the namespace `http.log.error`.
 - `logs.logger_names`: Map of request host to custom logger name. For example, if you wanted all requests for `example.com` to be emitted to a logger with a unique name, you can do `"example.com": "example"` and then all access logs related to requests for `example.com` will use a logger named `http.log.access.example` (and same for error logs, but with `.error.` in the name instead).
 
 #### http/servers/listen
@@ -1554,6 +1555,36 @@ The response flows ⬆️ **UP** (`file_server` -> `templates` -> `encode`):
 If you think of routes in this way, it will be easy and even fun to solve the puzzle of writing correct routes.
 
 
+##### http.handlers.cache
+
+A distributed HTTP cache.
+
+**NOTE: This module is a work-in-progress. It is not finished and is NOT ready for production use. [We need your help to finish it! Please volunteer in this issue.](https://github.com/caddyserver/caddy/issues/2820)**
+
+Caches only GET and HEAD requests. Honors the `Cache-Control: no-cache` header.
+
+Still TODO:
+
+- Eviction policies and API
+- Use single cache per-process
+- Preserve cache through config reloads
+- More control over what gets cached
+
+```json
+{
+	"handler": "cache",
+	"self": "",
+	"peers": [],
+	"max_size": 536870912
+}
+```
+
+- `self`: The network address of this cache instance; required.
+- `peers`: A list of network addresses of cache instances in the group.
+- `max_size`: Maximum size of the cache, in bytes. Default is 512 MB.
+
+
+
 ##### http.handlers.headers
 
 Modifies request or response headers.