Remove Gecko chrome-only getAttention() (#1302)

This isn't exposed to web contents. There isn't anything that it would
be useful to redirect to, so also remove existing redirects to the
removed page.

Needed for mdn/browser-compat-data#6942.

files/en-us/_redirects.txt

@@ -3747,7 +3747,6 @@
 /en-US/docs/DOM/window.frameElement	/en-US/docs/Web/API/window.frameElement
 /en-US/docs/DOM/window.frames	/en-US/docs/Web/API/window.frames
 /en-US/docs/DOM/window.fullScreen	/en-US/docs/Web/API/window.fullScreen
-/en-US/docs/DOM/window.getAttention	/en-US/docs/Web/API/window.getAttention
 /en-US/docs/DOM/window.getComputedStyle	/en-US/docs/Web/API/window.getComputedStyle
 /en-US/docs/DOM/window.getDefaultComputedStyle	/en-US/docs/Web/API/window/getDefaultComputedStyle
 /en-US/docs/DOM/window.getSelection	/en-US/docs/Web/API/window.getSelection
@@ -4270,7 +4269,6 @@
 /en-US/docs/DOM:window.frameElement	/en-US/docs/Web/API/window.frameElement
 /en-US/docs/DOM:window.frames	/en-US/docs/Web/API/window.frames
 /en-US/docs/DOM:window.fullScreen	/en-US/docs/Web/API/window.fullScreen
-/en-US/docs/DOM:window.getAttention	/en-US/docs/Web/API/window.getAttention
 /en-US/docs/DOM:window.getComputedStyle	/en-US/docs/Web/API/window.getComputedStyle
 /en-US/docs/DOM:window.getSelection	/en-US/docs/Web/API/window.getSelection
 /en-US/docs/DOM:window.history	/en-US/docs/Web/API/window.history
@@ -5120,7 +5118,6 @@
 /en-US/docs/Document_Object_Model_(DOM)/window.frameElement	/en-US/docs/Web/API/window.frameElement
 /en-US/docs/Document_Object_Model_(DOM)/window.frames	/en-US/docs/Web/API/window.frames
 /en-US/docs/Document_Object_Model_(DOM)/window.fullScreen	/en-US/docs/Web/API/window.fullScreen
-/en-US/docs/Document_Object_Model_(DOM)/window.getAttention	/en-US/docs/Web/API/window.getAttention
 /en-US/docs/Document_Object_Model_(DOM)/window.getComputedStyle	/en-US/docs/Web/API/window.getComputedStyle
 /en-US/docs/Document_Object_Model_(DOM)/window.getSelection	/en-US/docs/Web/API/window.getSelection
 /en-US/docs/Document_Object_Model_(DOM)/window.history	/en-US/docs/Web/API/window.history
@@ -11385,7 +11382,6 @@
 /en-US/docs/Web/API/Window.frameElement	/en-US/docs/Web/API/Window/frameElement
 /en-US/docs/Web/API/Window.frames	/en-US/docs/Web/API/Window/frames
 /en-US/docs/Web/API/Window.fullScreen	/en-US/docs/Web/API/Window/fullScreen
-/en-US/docs/Web/API/Window.getAttention	/en-US/docs/Web/API/Window/getAttention
 /en-US/docs/Web/API/Window.getComputedStyle	/en-US/docs/Web/API/Window/getComputedStyle
 /en-US/docs/Web/API/Window.getSelection	/en-US/docs/Web/API/Window/getSelection
 /en-US/docs/Web/API/Window.history	/en-US/docs/Web/API/Window/history
@@ -14771,7 +14767,6 @@
 /en-US/docs/window.focus	/en-US/docs/Document_Object_Model_(DOM)/window.focus
 /en-US/docs/window.forward	/en-US/docs/Web/API/window.forward
 /en-US/docs/window.frames	/en-US/docs/Web/API/window.frames
-/en-US/docs/window.getAttention	/en-US/docs/Web/API/window.getAttention
 /en-US/docs/window.getSelection	/en-US/docs/Web/API/window.getSelection
 /en-US/docs/window.history	/en-US/docs/Web/API/window.history
 /en-US/docs/window.home	/en-US/docs/Document_Object_Model_(DOM)/window.home

files/en-us/web/api/window/index.html

@@ -330,8 +330,6 @@ <h3 id="Deprecated_methods">Deprecated methods</h3>
  <dd>Registers the window to capture all events of the specified type.</dd>
  <dt>{{domxref("Window.forward()")}} {{Non-standard_inline}} {{deprecated_inline}}</dt>
  <dd>Moves the window one document forward in the history. This method is deprecated; you should instead use {{domxref("History.forward", "window.history.forward()")}}.</dd>
- <dt>{{domxref("Window.getAttention()")}} {{Non-standard_inline}} {{deprecated_inline}}</dt>
- <dd>Flashes the application icon.</dd>
  <dt>{{domxref("Window.home()")}} {{Non-standard_inline}} {{deprecated_inline}}</dt>
  <dd>Returns the browser to the home page.</dd>
  <dt>{{domxref("Window.openDialog()")}} {{Non-standard_inline}} {{deprecated_inline}}</dt>