ref-manual: Updated the SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS variable

Describes the new wildcard syntax

(From yocto-docs rev: e91db865686e7b1b9b21cb9aea892b0ed8884438)

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

documentation/ref-manual/ref-variables.xml

@@ -12720,8 +12720,25 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3"
                 </para>
 
                 <para>
-                    In this example, <filename>intone</filename> depends on
+                    In the previous example, <filename>intone</filename>
-                    <filename>mplayer2</filename>.
+                    depends on <filename>mplayer2</filename>.
+                </para>
+
+                <para>
+                    You can use the special token <filename>"*"</filename> on
+                    the left-hand side of the dependency to match all
+                    recipes except the one on the right-hand side.
+                    Here is an example:
+                    <literallayout class='monospaced'>
+    SIGGEN_EXCLUDE_SAFE_RECIPE_DEPS += "*->quilt-native"
+                    </literallayout>
+                </para>
+
+                <para>
+                    In the previous example, all recipes except
+                    <filename>quilt-native</filename> ignore task
+                    signatures from the <filename>quilt-native</filename>
+                    recipe when determining their task signatures.
                 </para>
 
                 <para>