[glibmm] Variant: Avoid . to not split an intro doc comment

[Daniel Boles <dboles src gnome org>]

commit 6c58c341dc369e4a89162168a5fa8146134492f8
Author: Daniel Boles <dboles src gmail com>
Date:   Sun Jan 5 11:38:10 2020 +0000

    Variant: Avoid . to not split an intro doc comment
    
    Doxygen interprets the first . to mean the end of the introductory
    blurb, so that resulted in this sentence suddenly ending after the "i."
    in "i.e." in the short version and having a line break there in the long

 glib/src/variant.hg | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/glib/src/variant.hg b/glib/src/variant.hg
index ff791df4..114d84c9 100644
--- a/glib/src/variant.hg
+++ b/glib/src/variant.hg
@@ -330,7 +330,7 @@ public:
 };
 
 /** The base class for multiple-item Variants, such as Variants containing
- * tuples or arrays, and also for maybe-typed (i.e. nullable) Variant types.
+ * tuples or arrays, and also for maybe-typed (that is, nullable) Variant types.
  *
  * @newin{2,28}
  * @ingroup Variant