Tweaked generation of Signals2 code snippets a bit.

[SVN r51662]

doc/Jamfile.v2

@@ -46,7 +46,7 @@ boostbook doc
     <dependency>../libs/units/doc//units
     <dependency>../libs/unordered/doc//unordered
     <dependency>../libs/thread/doc//thread
-    <dependency>../libs/signals2/doc/snippets//
+    <dependency>../libs/signals2/doc//hello_world_def_code_snippet.xml
 
     ## Add path references to the QuickBook generated docs...
 
@@ -67,6 +67,7 @@ boostbook doc
     <implicit-dependency>../libs/units/doc//units
     <implicit-dependency>../libs/unordered/doc//unordered
     <implicit-dependency>../libs/thread/doc//thread
+    <implicit-dependency>../libs/signals2/doc//hello_world_def_code_snippet.xml
 
     <xsl:param>boost.libraries=../../libs/libraries.htm
 

libs/signals2

@@ -1 +1 @@
-Subproject commit ae6d2d8d4789d2942ba3fdb9d99f8ae12599a325
+Subproject commit cab89ec6a6b30a6ca2781e399271e07ce0068667