[glibmm] Threads: Add a new doc line from the C docs.

[Murray Cumming <murrayc src gnome org>]

commit c52fd6eb60f3eadcc5bd60c5b0edb598ea22a9c0
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Aug 28 10:46:40 2013 +0200

    Threads: Add a new doc line from the C docs.

 glib/src/threads.hg |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/glib/src/threads.hg b/glib/src/threads.hg
index 9e536cc..52bb4b4 100644
--- a/glib/src/threads.hg
+++ b/glib/src/threads.hg
@@ -137,6 +137,7 @@ public:
    * in C++11, std::bind() or a C++11 lambda expression instead of sigc::mem_fun().
    *
    * The @a name can be useful for discriminating threads in a debugger.
+   * It is not used for other purposes and does not have to be unique.
    * Some systems restrict the length of @a name to 16 bytes.
    *
    * @param slot A slot to execute in the new thread.