docs: Clarified how to find out when a switch is toggled

Per Chris, the existing doc was incorrect: you *can't* check for a
button press and a switch flip the same way. (The button triggers a
click event, but the switch does not.) Chris suggested that we just
remove the reference to onClick and suggest using a listener for
both kinds of buttons (ToggleButton and Switch).

Also pulled one note out of a section where it didn't fit (the bit
about changing a button/switch's state programmatically didn't have
much to do with listening for clicks) and put it at the top, and I
fixed a Javadoc typo for a relevant class that I happened to notice.

See first comment for doc stage location.

bug: 20625504
Change-Id: I9c8975111381e5b169f6a61454ef3a93da635759
diff --git a/core/java/android/widget/Switch.java b/core/java/android/widget/Switch.java
index 7a22224..585a84d 100644
--- a/core/java/android/widget/Switch.java
+++ b/core/java/android/widget/Switch.java
@@ -57,7 +57,7 @@
  * {@link #setTextAppearance(android.content.Context, int) textAppearance} and the related
  * setTypeface() methods control the typeface and style of label text, whereas the
  * {@link #setSwitchTextAppearance(android.content.Context, int) switchTextAppearance} and
- * the related seSwitchTypeface() methods control that of the thumb.
+ * the related setSwitchTypeface() methods control that of the thumb.
  *
  * <p>See the <a href="{@docRoot}guide/topics/ui/controls/togglebutton.html">Toggle Buttons</a>
  * guide.</p>