Added images: Line Numbers window, Cross-reference window (en)

Web/OfficeWeb/apps/documenteditor/main/resources/help/en/UsageInstructions/InsertCrossReference.htm

@@ -21,6 +21,7 @@
             <li>Go to the <b>References</b> tab and click on the <b>Cross-reference</b> icon.</li>
             <li>
                 Set the required parameters in the opened <b>Cross-reference</b> window:
+                <p><img alt="Cross-reference window" src="../images/cross_refference_window.png" /></p>
                 <ul>
                     <li>The <b>Reference type</b> drop-down menu specifies the item you wish to refer to, i.e. a numbered item (set by default), <em>a heading, a bookmark, a footnote, an endnote, an equation, a figure,</em> and <em>a table</em>. Choose the required item type.</li>
                     <li>

Web/OfficeWeb/apps/documenteditor/main/resources/help/en/UsageInstructions/InsertLineNumbers.htm

@@ -30,6 +30,7 @@
             </li>
             <li>
                 Specify the advanced parameters if needed. Click the <b>Line Numbering Options</b> item in the <b>Line Numbers</b> drop-down menu. Check the <b>Add line numbering</b> box to apply the line numbering to the document and to access the advanced parameters of the option:
+                <p><img alt="Line Numbering window" src="../images/linenumbers_window.png" /></p>
                 <ul>
                     <li><b>Start at</b> sets the starting numeric value of the line numbering sequence. The parameter is set to <b>1</b> by default.</li>
                     <li><b>From text</b> specifies the distance between the line numbers and the text. Enter the required value in cm. The parameter is set to <b>Auto</b> by default.</li>