Doc: Update info about opening output panes

- Describe additional ways to open output panes.
- Add a screenshot of the taskbar.
- Add descriptions of related icons.
- Fix the Maximize Output Pane command keyboard shortcut.

Task-number: QTCREATORBUG-26278
Change-Id: I92712d1542871119e4402df18bd10c9563a335d3
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

doc/qtcreator/src/howto/creator-only/creator-how-tos.qdoc

@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2019 The Qt Company Ltd.
+** Copyright (C) 2021 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the Qt Creator documentation.
@@ -116,30 +116,25 @@
 
     \section1 Open output panes
 
-    The output panes provide a list of errors and warnings encountered during
-    a build, detailed output from the compiler, status of a program when it is
-    executed and debug output, as well as search results.
+    The \l{Viewing Output}{output panes} provide a list of errors and warnings
+    encountered during a build, detailed output from the compiler, status of a
+    program when it is executed, debug output, and search results.
 
     To open output panes, use the following shortcuts:
 
     \list
 
-        \li \uicontrol{Issues} pane Alt+1 (Cmd+1 on \macos)
+        \li \uicontrol{Issues} - \key Alt+1 (\key Cmd+1 on \macos)
 
-        \li \uicontrol{Search Results} pane Alt+2 (Cmd+2 on \macos)
+        \li \uicontrol{Search Results} - \key Alt+2 (\key Cmd+2 on \macos)
 
-        \li \uicontrol{Application Output} pane Alt+3 (Cmd+3 on \macos)
+        \li \uicontrol{Application Output} - \key Alt+3 (\key Cmd+3 on \macos)
 
-        \li \uicontrol{Compile Output} pane Alt+4 (Cmd+4 on \macos)
+        \li \uicontrol{Compile Output} - \key Alt+4 (\key Cmd+4 on \macos)
 
     \endlist
 
-    To open the other output panes, such as \uicontrol{General Messages} and
-    \uicontrol{Version Control}, select \uicontrol View >
-    \uicontrol {Output Panes}. The menu items also display
-    the keyboard shortcuts that you can use.
-
-    For more information about output panes, see \l{Viewing Output}.
+    For additional ways to open all output panes, see \l{Viewing Output}.
 
     \section1 Find keyboard shortcuts
 

doc/qtcreator/src/user-interface/creator-ui.qdoc

@@ -384,9 +384,24 @@
 
     \endlist
 
-    Output panes are available in all \l{Selecting Modes}{modes}. Click the name
-    of an output pane to open the pane. To maximize an open output pane, click
-    the \uicontrol {Maximize Output Pane} button or press \key {Alt+9}.
+    Output panes are available on the taskbar in all \l{Selecting Modes}{modes}.
+
+    \image qtcreator-output-panes-taskbar.png "Output panes on the taskbar"
+
+    You can open output panes in the following ways:
+
+    \list
+        \li Select the output pane on the taskbar.
+        \li Select \key Alt (\key Cmd on \macos) and the number of the pane on
+            the taskbar.
+        \li Select \inlineimage icons/output-pane-menu.png
+            , and then select the pane to open.
+        \li Select \uicontrol View > \uicontrol {Output Panes}.
+            The menu items also display the keyboard shortcuts that you can use.
+    \endlist
+
+    To maximize an open output pane, select the \inlineimage arrowup.png
+    (\uicontrol {Maximize Output Pane}) button or press \key {Alt+Shift+9}.
 
 
     To increase or decrease the output text size, select \inlineimage plus.png