docs(mkdocs) add display index preferences section

docs/common-workflows/set-display-index.md

@@ -0,0 +1,17 @@
+# Setting a Given Display to a Specific Index
+
+If you would like `komorebi` to remember monitor index positions, you will need to set the `display_index_preferences`
+configuration option in the static configuration file.
+
+Display IDs can be found using `komorebic monitor-information`.
+
+Then, in `komorebi.json`, you simply need to specify the preferred index position for each display ID:
+
+```json
+{
+  "display_index_preferences": {
+    "0": "DEL4310-5&1a6c0954&0&UID209155",
+    "1": "<another-display_id>"
+  }
+}
+```