Fixed example links in docs.

Fixes https://github.com/boostorg/iterator/issues/52.

doc/quickbook/indirect_iterator.qbk

@@ -1,4 +1,3 @@
-
 [section:indirect Indirect Iterator]
 
 `indirect_iterator` adapts an iterator by applying an
@@ -73,7 +72,7 @@ The output is:
 
 
 The source code for this example can be found 
-[@../example/indirect_iterator_example.cpp here].
+[example_link indirect_iterator_example.cpp..here].
 
 
 [h2 Reference]
@@ -251,4 +250,4 @@ following operations:
 [*Effects: ] `--m_iterator`[br]
 [*Returns: ] `*this`
 
-[endsect]
+[endsect]