dev-manual: Added check-upgrade-status blurb to upgrading recipes

The section "Upgrading Recipes" covers several ways of
upgrading a recipe.  I added some stuff in the introductory
area that mentions the fact a user might want to check
the upgrade status of a recipe first.

(From yocto-docs rev: 6747335d429b58251642c6b82d7725b0fe3e686e)

Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-common-tasks.xml

@@ -4196,11 +4196,27 @@
             built by layer recipes.
             It is recommended to keep recipes up-to-date with upstream
             version releases.
+        </para>
+
+        <para>
+            While several methods exist that allow you upgrade a recipe,
+            you might consider checking on the upgrade status of a recipe
+            first.
+            You can do so using the
+            <filename>devtool check-upgrade-status</filename> command.
+            See the
+            "<ulink url='&YOCTO_DOCS_REF_URL;#devtool-checking-on-the-upgrade-status-of-a-recipe'>Checking on the Upgrade Status of a Recipe</ulink>"
+            section in the Yocto Project Reference Manual for more information.
+        </para>
+
+        <para>
+            The remainder of this section describes three ways you can
+            upgrade a recipe.
             You can use the Automated Upgrade Helper (AUH) to set up
             automatic version upgrades.
             Alternatively, you can use <filename>devtool upgrade</filename>
             to set up semi-automatic version upgrades.
-            Finally, you can even manually upgrade a recipe by editing the
+            Finally, you can manually upgrade a recipe by editing the
             recipe itself.
         </para>