[glibmm] Glib::Variant—Improve documentation of get_maybe()

[Daniel Boles <dboles src gnome org>]

commit 4462970be0fc91a5ddc22d580c46d8a86ea0be69
Author: Daniel Boles <dboles src gnome org>
Date:   Mon Feb 13 15:43:50 2017 +0000

    Glib::Variant—Improve documentation of get_maybe()
    
    Clarify what is set and returned, and use lower case “nothing” to match
    how that must be written in GVariant text format, à la GSettings, etc.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=778219

 glib/src/variant.hg |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)
---
diff --git a/glib/src/variant.hg b/glib/src/variant.hg
index 280f3b3..92e0b6b 100644
--- a/glib/src/variant.hg
+++ b/glib/src/variant.hg
@@ -387,11 +387,12 @@ public:
   DataType get_child(gsize index = 0) const;
   */
 
-  /** If this is a maybe-typed instance, extract its value. If the value is
-   * Nothing, then this function returns <tt>false</tt>.
+  /** If this is a maybe-typed instance, try to extract its value. If there is
+   * no value (the value is <tt>nothing</tt>), return <tt>false</tt. Otherwise,
+   * the value is copied to the supplied Variant and <tt>true</tt> is returned.
    *
-   * @param maybe A place in which to return the value (the value may be
-   * <tt>0</tt>).
+   * @param maybe A place in which to return the value, if it isn’t
+   * <tt>nothing</tt>.
    * @newin{2,28}
    */
   bool get_maybe(VariantBase& maybe) const;