scalc: Add missing labelling

The "first page number" spin button was missing accessibility labelling.

Change-Id: I750cebf33f20056819abc00bb6875e2d89100fdd
Reviewed-on: https://gerrit.libreoffice.org/51291Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Katarina Behrens <Katarina.Behrens@cib.de>

sc/uiconfig/scalc/ui/sheetprintpage.ui

@@ -103,6 +103,9 @@
                         <property name="use_underline">True</property>
                         <property name="xalign">0</property>
                         <property name="draw_indicator">True</property>
+                        <accessibility>
+                          <relation type="label-for" target="spinED_PAGENO"/>
+                        </accessibility>
                       </object>
                       <packing>
                         <property name="left_attach">0</property>
@@ -116,6 +119,9 @@
                         <property name="max_length">5</property>
                         <property name="invisible_char">•</property>
                         <property name="adjustment">adjustmentFirstPage</property>
+                        <accessibility>
+                          <relation type="labelled-by" target="checkBTN_PAGENO"/>
+                        </accessibility>
                       </object>
                       <packing>
                         <property name="left_attach">1</property>