[libsigcplusplus] Reference docs: main page: Use @c to monospace function names.

[Murray Cumming <murrayc src gnome org>]

commit 22c85af1ff9e1a9ef5c8ccc63fe24f521d47574d
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Mar 15 12:40:57 2016 +0100

    Reference docs: main page: Use @c to monospace function names.

 sigc++/sigc++.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/sigc++/sigc++.h b/sigc++/sigc++.h
index 68442b5..54c07d4 100644
--- a/sigc++/sigc++.h
+++ b/sigc++/sigc++.h
@@ -78,7 +78,7 @@
  * yourprogram_LDADD = $(DEPS_LIBS)
  * @endcode
  *
- * Your PKG_CHECK_MODULES() call should also mention any other libraries that
+ * Your @c PKG_CHECK_MODULES() call should also mention any other libraries that
  * you need to use via pkg-config.
  *
  * @subsection cmake Using CMake
@@ -91,7 +91,7 @@
  * target_link_libraries(yourprogram ${DEPS_LIBRARIES})
  * @endcode
  *
- * Your pkg_check_modules() call should also mention any other libraries that
+ * Your @c pkg_check_modules() call should also mention any other libraries that
  * you need to use via pkg-config.
  *
  * @section scope Scope of Documentation