[libadwaita] version: Document ADW_VERSION

[Alexander Mikhaylenko <alexm src gnome org>]

commit a4ff965a4dae1e53861aef8734228fe87e1cc0e5
Author: Maximiliano Sandoval R <msandova gnome org>
Date:   Tue Dec 7 12:45:33 2021 +0100

    version: Document ADW_VERSION

 src/adw-version.h.in | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/adw-version.h.in b/src/adw-version.h.in
index a0a445d6..f66acaba 100644
--- a/src/adw-version.h.in
+++ b/src/adw-version.h.in
@@ -36,9 +36,9 @@ G_BEGIN_DECLS
 #define ADW_MICRO_VERSION              (@ADW_MICRO_VERSION@)
 
 /**
- * ADW_VERSION
+ * ADW_VERSION:
  *
- * Adw version.
+ * Adwaita version (e.g. 1.2.3).
  */
 #define ADW_VERSION                    (@ADW_VERSION@)