add tooltips to left/right buttons in toc token widget scrolling area

Change-Id: I05fcf614c6e1829633f2265e8c48189664d6ec60
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/196629
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>

solenv/sanitizers/ui/modules/swriter.suppr

@@ -144,8 +144,6 @@ sw/uiconfig/swriter/ui/tabletextflowpage.ui://GtkLabel[@id='label39'] orphan-lab
 sw/uiconfig/swriter/ui/textgridpage.ui://GtkLabel[@id='labelFT_CHARRANGE'] orphan-label
 sw/uiconfig/swriter/ui/textgridpage.ui://GtkLabel[@id='labelFT_LINERANGE'] orphan-label
 sw/uiconfig/swriter/ui/titlepage.ui://GtkSpinButton[@id='NF_PAGE_START'] missing-label-for
-sw/uiconfig/swriter/ui/tokenwidget.ui://GtkButton[@id='left'] button-no-label
-sw/uiconfig/swriter/ui/tokenwidget.ui://GtkButton[@id='right'] button-no-label
 sw/uiconfig/swriter/ui/toxbuttonwidget.ui://GtkToggleButton[@id='button'] button-no-label
 sw/uiconfig/swriter/ui/toxentrywidget.ui://GtkEntry[@id='entry'] no-labelled-by
 sw/uiconfig/swriter/ui/unfloatbutton.ui://GtkButton[@id='button'] button-no-label

sw/uiconfig/swriter/ui/tokenwidget.ui

@@ -22,6 +22,7 @@
         <property name="visible">True</property>
         <property name="can-focus">True</property>
         <property name="receives-default">True</property>
+        <property name="tooltip_text" translatable="yes" context="tokenwidget|left|tooltip_text">Scroll left</property>
         <property name="image">image1</property>
         <property name="always-show-image">True</property>
       </object>
@@ -84,6 +85,7 @@
         <property name="visible">True</property>
         <property name="can-focus">True</property>
         <property name="receives-default">True</property>
+        <property name="tooltip_text" translatable="yes" context="tokenwidget|right|tooltip_text">Scroll right</property>
         <property name="image">image2</property>
         <property name="always-show-image">True</property>
       </object>