[vala] Document --api-version in the man page

[Luca Bruno <lucabru src gnome org>]

commit 6fd955f5cbb539f6148515b25b9f0bd402226982
Author: Luca Bruno <lucabru src gnome org>
Date:   Thu Nov 29 17:48:38 2012 +0100

    Document --api-version in the man page

 doc/valac.1 |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/doc/valac.1 b/doc/valac.1
index 6159db3..e31103c 100644
--- a/doc/valac.1
+++ b/doc/valac.1
@@ -48,6 +48,9 @@ Output directory
 .B \--version
 Display version number
 .TP
+.B \--api-version
+Display API version number
+.TP
 .B \-C, --ccode
 Output C code
 .TP