docs: add /server/history/totals to documentation

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

docs/web_api.md

@@ -2308,6 +2308,36 @@ An array of requsted historical jobs:
 }
 ```
 
+#### Get job totals
+HTTP request:
+```http
+GET /server/history/totals
+```
+JSON-RPC request:
+```json
+{
+    "jsonrpc": "2.0",
+    "method":"server.history.totals",
+    "id": 5656
+}
+```
+
+Returns:
+
+An object containing the following total job statistics:
+```json
+{
+    "job_totals": {
+        "total_jobs": 3,
+        "total_time": 11748.077333278954,
+        "total_print_time": 11348.794790096988,
+        "total_filament_used": 11615.718840001999,
+        "longest_job": 11665.191012736992,
+        "longest_print": 11348.794790096988
+    }
+}
+```
+
 #### Get a single job
 HTTP request:
 ```http