Added documentation for darktable.gui.mimic

content/lua.api.manual/darktable/gui/mimic.md

@@ -0,0 +1,38 @@
+---
+title: darktable.gui.mimic
+id: action
+weight: 60
+draft: false
+author: "people"
+---
+
+```
+function(
+  widget_type : string,
+  name : string,
+  callback : function
+)
+```
+
+Provides a virtual widget that can be assigned to a shortcut.
+
+* **widget_type** - _string_ - The type of widget to mimic, one of: button, slider, dropdown.
+* **name** - _string_ - The name of the virtual widget that a shortcut can be assigned to.
+* **callback** - _function_ - A function containing [darktable.gui.action](../gui/action.md) calls to execute.
+
+## Example
+
+```
+local dt = require "darktable"
+
+dt.gui.mimic("slider", "multi-contrast",
+  function(action, element, effect, size)
+      if dt.gui.action("iop/filmicrgb", "focus") == 1 then
+        which = "iop/filmicrgb/contrast"
+      else
+        which = "iop/colorbalancergb/contrast"
+      end
+      return dt.gui.action(which, element, effect, size)
+    end
+)
+```