docs: Add new endpints to API documention

Signed-off-by:  Eric Callahan <arksine.code@gmail.com>

docs/api_changes.md

@@ -1,6 +1,12 @@
 This document keeps a record of all changes to Moonraker's remote
 facing APIs.
 
+### September 30th 2020
+- Two new endpoints have been added:
+  - `GET /server/info` (`server.info`)
+  - `GET /server/gcode_store` (`server.gcode_store`)
+  See web_api.md for details on their usage.
+
 ### September 7th 2020
 - A new websocket API has been added, `server.files.delete_file`:
   ```

docs/web_api.md

@@ -166,8 +166,8 @@ that uses promises to return responses and errors (see json-rcp.js).
       ...}
     }
   ```
-  Note that Moonraker's current behavior is maintain a superset of all client
-  subscriptions, thus you may received data for objects that you did not
+  Note that Moonraker's current behavior is to maintain a superset of all
+  subscriptions, thus you may receive updates for objects that you did not
   request.  This behavior is subject to change in the future (where each
   client receives only the subscriptions it requested).
 
@@ -192,6 +192,29 @@ that uses promises to return responses and errors (see json-rcp.js).
    z: "open"}
 ```
 
+### Query Server Info
+- HTTP command:\
+  `GET /server/info`
+
+- Websocket command:
+  `{jsonrpc: "2.0", method: "server.info", id: <request id>}`
+
+- Returns:\
+  An object containing the server's state, structured as follows:
+
+```json
+  {
+    klippy_connected: <bool>,
+    klippy_state: <string>,
+    plugins: [<strings>]
+  }
+```
+  Note that `klippy_state` will match the `state` value received from
+  `/printer/info`. The `klippy_connected` item tracks the state of the
+  connection to Klippy. The `plugins` key will return a list of all
+  enabled plugins.  This can be used by clients to check if an optional
+  plugin is available.
+
 ### Fetch stored temperature data
 - HTTP command:\
   `GET /server/temperature_store`
@@ -206,6 +229,32 @@ that uses promises to return responses and errors (see json-rcp.js).
   array is organized from oldest temperature to most recent (left to right).
   Note that when the host starts each array is initialized to 0s.
 
+### Fetch stored gcode info
+- HTTP command:\
+  `GET /server/gcode_store`
+
+  Optionally, a `count` argument may be added to specify the number of lines fetch.
+  If omitted, the entire gcode store will be sent (up to 1000 lines).
+
+  `GET /server/gcode_store?count=100`
+
+- Websocket command:
+  `{jsonrpc: "2.0", method: "server.gcode_store", id: <request id>}`
+
+  OR
+  `{jsonrpc: "2.0", method: "server.gcode_store",
+   params: {count: <integer>} id: <request id>}`
+
+- Returns:\
+  An object which includes a string containing up to 1000 lines of
+  stored gcode responses.  Each line will be separated by a newline
+  character:
+```json
+  {
+    gcode_store: <string>
+  }
+```
+
 ## Gcode Controls
 
 ### Run a gcode: