dev-manual: Added new section on recipe style guidelines

Fixes [YOCTO #10360]

Added a new section to reference into the OpenEmbedded Styleguide.
This will help people writing new recipes to conform to known
styles.

(From yocto-docs rev: 40c12742c78f5aba5bb4e43f759e8c478470fd83)

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

@@ -3368,6 +3368,28 @@
                 </para>
             </section>
         </section>
+
+        <section id="following-recipe-style-guidelines">
+            <title>Following Recipe Style Guidelines</title>
+
+            <para>
+                When writing recipes, it is good to conform to existing
+                style guidelines.
+                The
+                <ulink url='http://www.openembedded.org/wiki/Styleguide'>OpenEmbedded Styleguide</ulink>
+                wiki page provides rough guidelines for preferred recipe style.
+            </para>
+
+            <para>
+                It is common for existing recipes to deviate a bit from this
+                style.
+                However, aiming for at least a consistent style is a good idea.
+                Some practices, such as omitting spaces around
+                <filename>=</filename> operators in assignments or ordering
+                recipe components in an erratic way, are widely seen as poor
+                style.
+            </para>
+        </section>
     </section>
 
     <section id="platdev-newmachine">