[I18N] Improve doc-page of CSV transaction importer

Text based on
https://lists.gnucash.org/pipermail/gnucash-devel/2019-May/043795.html

gnucash/gtkbuilder/assistant-csv-trans-import.glade

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- Generated with glade 3.20.4 -->
+<!-- Generated with glade 3.22.1 -->
 <interface>
   <requires lib="gtk+" version="3.10"/>
   <object class="GtkListStore" id="account_match_store">
@@ -1080,17 +1080,20 @@ For example
           <object class="GtkLabel" id="label8">
             <property name="visible">True</property>
             <property name="can_focus">False</property>
-            <property name="label" translatable="yes">On the following page you will be able to associate each transaction to a category.
+            <property name="label" translatable="yes">If you click "Next" Gnucash will perform a number of checks.
 
-If there were problems with the import settings, pressing forward will take you back to the preview page to try and correct.
+If one of those &lt;i&gt;checks fails&lt;/i&gt; you'll be automatically redirected to the preview page to try and correct.
 
-If this is the first time importing, you will find that all lines may need to be associated. On subsequent imports, the importer will try to associate the transactions based on previous imports.
+On the following page you will be able to associate each transaction to a category.
 
-If this is your initial import into a new file, you will first see a dialog for setting book options, since these can affect how imported data are converted to GnuCash transactions. If this is an existing file, the dialog will not be shown.
+If this is your &lt;i&gt;initial import into a new file&lt;/i&gt;, you will first see a dialog for setting book options, since these can affect how imported data are converted to GnuCash transactions. If this is an existing file, the dialog will not be shown.
+
+If this is the &lt;i&gt;first time importing&lt;/i&gt;, you will find that all lines may need to be associated. On subsequent imports, the importer will try to associate the transactions based on previous imports.
 
 The confidence of a correct association is displayed as a colored bar.
 
 More information can be displayed by using the help button.</property>
+            <property name="use_markup">True</property>
             <property name="wrap">True</property>
           </object>
           <packing>