Make Ctrl+T shortcut to work for "Open tab" in "Execute SQL"

This shortcut was set for the following actions, making it ambiguous:
"View > DB Toolbar" and "Open tab" in "Execute SQL". Additionally it was
used by QScintilla for transposing lines.

Shortcut for "View > DB Toolbar" has been removed, since it's not
considered a frequently used action and there are other toolbars without
shortcut. The shortcut for QScintilla has been changed to "Ctrl+Shift+Up".

The now working shortcut is added to the "Open tab" action's tool-tip for
documentation purposes.

See issue #1647

src/MainWindow.cpp

@@ -512,6 +512,7 @@ void MainWindow::init()
     addShortcutsTooltip(ui->buttonRefresh, {shortcutBrowseRefreshF5->key(), shortcutBrowseRefreshCtrlR->key()});
     addShortcutsTooltip(ui->buttonPrintTable, {shortcutPrint->key()});
 
+    addShortcutsTooltip(ui->actionSqlOpenTab);
     addShortcutsTooltip(ui->actionSqlPrint);
     addShortcutsTooltip(ui->actionExecuteSql, {shortcutBrowseRefreshF5->key(), shortcutBrowseRefreshCtrlR->key()});
     addShortcutsTooltip(ui->actionSqlExecuteLine);

src/MainWindow.ui

@@ -1684,9 +1684,6 @@ You can drag SQL statements from the Schema column and drop them into the SQL ed
    <property name="whatsThis">
     <string>Shows or hides the Database toolbar.</string>
    </property>
-   <property name="shortcut">
-    <string>Ctrl+T</string>
-   </property>
    <property name="menuRole">
     <enum>QAction::NoRole</enum>
    </property>

src/sqltextedit.cpp

@@ -34,6 +34,10 @@ SqlTextEdit::SqlTextEdit(QWidget* parent) :
     command = standardCommands()->boundTo(Qt::ControlModifier+Qt::ShiftModifier+Qt::Key_Slash);
     command->setKey(0);
 
+    // Change command binding for Ctrl+T so it doesn't interfere with "Open tab"
+    command = standardCommands()->boundTo(Qt::ControlModifier+Qt::Key_T);
+    command->setKey(Qt::ControlModifier+Qt::ShiftModifier+Qt::Key_Up);
+
     QShortcut* shortcutToggleComment = new QShortcut(QKeySequence(tr("Ctrl+/")), this, nullptr, nullptr, Qt::WidgetShortcut);
     connect(shortcutToggleComment, &QShortcut::activated, this, &SqlTextEdit::toggleBlockComment);