Document the Overview and other new things

wiki/Configuration:-Miscellaneous.md

@@ -1,5 +1,3 @@
-### Overview
-
 This page documents all top-level options that don't otherwise have dedicated pages.
 
 Here are all of these options at a glance:
@@ -25,6 +23,10 @@ cursor {
     hide-after-inactive-ms 1000
 }
 
+overview {
+    zoom 0.5
+}
+
 clipboard {
     disable-primary
 }
@@ -143,6 +145,22 @@ cursor {
 }
 ```
 
+### `overview`
+
+<sup>Since: next release</sup>
+
+Settings for the [Overview](./Overview.md).
+
+`zoom` controls how much the workspaces zoom out in the overview.
+It ranges from 0 to 0.75 where lower values make everything smaller.
+
+```kdl
+// Make workspaces four times smaller than normal in the overview.
+overview {
+    zoom 0.25
+}
+```
+
 ### `clipboard`
 
 <sup>Since: 25.02</sup>