dev-manual: Grammar fix to kickstart section.

The "Generate an Image Using an Existing Kickstart File"
section had a missing subject.  Fixed it.

(From yocto-docs rev: 7ab6d1422690373e59d681e423a80595879788b4)

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

@@ -4102,8 +4102,8 @@
                 </para>
 
                 <para>
-                    The output specifies the exact created as well as where
-                    it was created.
+                    The output specifies the exact image created as well as
+                    where it was created.
                     The output also names the artifacts used and the exact
                     <filename>.wks</filename> script that was used to generate
                     the image.