mention async updates in docs

packages/core/src/components/forms/text-inputs.md

@@ -9,7 +9,8 @@ Blueprint provides two ways to create a text input:
 
 @## Input group
 
-An input group allows you to add icons and buttons _within_ a text input to expand its
+Input groups are a basic building block used to render text inputs across many Blueprint components.
+They allow you to add icons and buttons _within_ a text input to expand its appearance and
 functionality. For example, you might use an input group to build a visibility toggle for a password
 field.
 
@@ -28,6 +29,12 @@ a controlled or uncontrolled fashion. In addition to its own props, it supports
 all valid props for HTML `<input>` elements and proxies them to that element in
 the DOM; the most common ones are detailed below.
 
+If controlled with the `value` prop, `InputGroup` has support for _asynchronous updates_, which may
+occur with some form handling libraries like `redux-form`. This is not generally encouraged (a value
+returned from `onChange` should generally be sent back to the component as a controlled `value` synchronously),
+but there is basic support for it. Note that the input cursor may jump to the end of the input if the speed
+of text entry (time between change events) is faster than the speed of the async update.
+
 @interface IInputGroupProps
 
 @### CSS