ref-manual: Review edits to classes "E" through "G"

extrausers - Changed the note to try and describe that the
  change is still specific to an image recipe but is not
  tied to other individual recipes.

fontcache - Minor fix.

gtk-icon-cache - fixed capitalization issue.

gtk-immodules-cache - Minor fix

gzipnative - Minor fix.

(From yocto-docs rev: bc25a62de2345b7ec0b2b019ff399921ec6edd0a)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/ref-classes.xml

@@ -677,11 +677,11 @@
         <note>
             The user and group operations added using the
             <filename>extrausers</filename> class are not tied to a specific
-            recipe but can be performed across the image as a whole.
+            recipe outside of the recipe for the image.
-            See the
+            Thus, the operations can be performed across the image as a whole.
+            Use the
             <link linkend='ref-classes-useradd'><filename>useradd</filename></link>
-            class for information on how to add user and group configuration
+            class to add user and group configuration to a specific recipe.
-            to a specific recipe.
         </note>
     </para>
 
@@ -720,7 +720,7 @@
         If the fonts being installed are in packages other than the main
         package, set
         <link linkend='var-FONT_PACKAGES'><filename>FONT_PACKAGES</filename></link>
-        to include the packages containing the fonts.
+        to specify the packages containing the fonts.
     </para>
 </section>
 
@@ -762,8 +762,7 @@
         <link linkend='ref-classes-gtk-icon-cache'><filename>gtk-icon-cache</filename></link>,
         <link linkend='ref-classes-gconf'><filename>gconf</filename></link> and
         <link linkend='ref-classes-mime'><filename>mime</filename></link> classes.
-        The class also disables GLib Object System (Gobject) introspection
+        The class also disables Gobject introspection where applicable.
-        where applicable.
     </para>
 </section>
 
@@ -853,7 +852,7 @@
 
     <para>
         The <filename>gtk-icon-cache</filename> class
-        Generates the proper post-install and post-remove (postinst/postrm)
+        generates the proper post-install and post-remove (postinst/postrm)
         scriptlets for packages that use GTK+ and install icons.
         These scriptlets call <filename>gtk-update-icon-cache</filename> to add
         the fonts to GTK+'s icon cache.
@@ -884,7 +883,7 @@
         If the input method modules being installed are in packages other than
         the main package, set
         <link linkend='var-GTKIMMODULES_PACKAGES'><filename>GTKIMMODULES_PACKAGES</filename></link>
-        to include the packages containing the modules.
+        to specify the packages containing the modules.
     </para>
 </section>
 
@@ -894,7 +893,8 @@
     <para>
         The <filename>gzipnative</filename>
         class enables the use of native versions of <filename>gzip</filename>
-        and <filename>pigz</filename> rather than the system versions.
+        and <filename>pigz</filename> rather than the versions of these tools
+        from the build host.
     </para>
 </section>