Add back event slices tooltip

Add back event slices tooltip which got lost in the re-layout of SANS
settings

scripts/Interface/ui/sans_isis/sans_data_processor_window.ui

@@ -855,6 +855,11 @@ QGroupBox::title {
                          <property name="enabled">
                           <bool>true</bool>
                          </property>
+                         <property name="toolTip">
+                         <string>
+                         &lt;html&gt;&lt;head/&gt;&lt;body&gt;&lt;p&gt;In the case of data which was measured in event-mode, it is possible to perform time-of-flight slices of the data and reduce these separately.&lt;/p&gt;&lt;p&gt;Input can be:&lt;/p&gt;&lt;p&gt;-&lt;span style=&quot; font-style:italic;&quot;&gt; start:step:stop&lt;/span&gt; specifies time slices from the &lt;span style=&quot; font-style:italic;&quot;&gt;start&lt;/span&gt; value to the &lt;span style=&quot; font-style:italic;&quot;&gt;stop &lt;/span&gt;value in steps of &lt;span style=&quot; font-style:italic;&quot;&gt;step&lt;/span&gt;&lt;/p&gt;&lt;p&gt;- &lt;span style=&quot; font-style:italic;&quot;&gt;start-stop &lt;/span&gt;which specifies a time slice from the &lt;span style=&quot; font-style:italic;&quot;&gt;start&lt;/span&gt; value to the &lt;span style=&quot; font-style:italic;&quot;&gt;stop&lt;/span&gt; value&lt;/p&gt;&lt;p&gt;- &lt;span style=&quot; font-style:italic;&quot;&gt;&amp;gt;start&lt;/span&gt; specifies a slice from the &lt;span style=&quot; font-style:italic;&quot;&gt;start &lt;/span&gt;value to the end of the data set&lt;/p&gt;&lt;p&gt;- &lt;span style=&quot; font-style:italic;&quot;&gt;&amp;lt;stop&lt;/span&gt; specifes a slice from the start of the data set to the &lt;span style=&quot; font-style:italic;&quot;&gt;stop &lt;/span&gt;value&lt;/p&gt;&lt;p&gt;In addition it is possible to concatenate these specifications using comma-separation. An example is:&lt;/p&gt;&lt;p&gt;&lt;span style=&quot; font-style:italic;&quot;&gt;5-10,12:2:16,20-30&lt;/span&gt;&lt;/p&gt;&lt;/body&gt;&lt;/html&gt;
+                         </string>
+                         </property>
                         </widget>
                        </item>
                        <item row="3" column="0">