ref-manual: Review edits to do_populate_sysroot and SYSROOT_DIRS_NATIVE

Fixes [YOCTO #10377]

Some minor wordsmithing.  Also added a new note to the
SYSROOT_DIRS_NATIVE variable.

(From yocto-docs rev: 459666b01b8d6d8212a59c877ea6c324511a5883)

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

documentation/ref-manual/ref-variables.xml

@@ -13210,6 +13210,13 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
          ${localstatedir} \
      "
                     </literallayout>
+                    <note>
+                        Programs built by <filename>-native</filename> recipes
+                        run directly from the sysroot
+                        (<filename>STAGING_DIR_NATIVE</filename>), which is
+                        why additional directories containing program
+                        executables and supporting files need to be staged.
+                    </note>
                 </para>
             </glossdef>
         </glossentry>