[gtkmm] FileFilter: Format docs copied in from GTK better

[Daniel Boles <dboles src gnome org>]

commit 114d6660ee498faaccc20adc04af07f00711d6a9
Author: Daniel Boles <dboles src gmail com>
Date:   Fri Dec 21 18:57:00 2018 +0000

    FileFilter: Format docs copied in from GTK better
    
    Capitalise MIME, and put <tt> tags around the MIME types.

 gtk/src/filefilter.hg | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/gtk/src/filefilter.hg b/gtk/src/filefilter.hg
index 49755595..016f018d 100644
--- a/gtk/src/filefilter.hg
+++ b/gtk/src/filefilter.hg
@@ -28,13 +28,14 @@ namespace Gtk
  *
  * A Gtk::FileFilter can be used to restrict the files being shown in a Gtk::FileChooser.
  * Files can be filtered based on their name (with add_pattern()),
- * on their mime type (with add_mime_type()), or by a custom filter
+ * on their MIME type (with add_mime_type()), or by a custom filter
  * function (with add_custom()).
  *
- * Filtering by mime types handles aliasing and subclassing of mime types;
- * e.g. a filter for text/plain also matches a file with mime type application/rtf,
- * since application/rtf is a subclass of text/plain. Note that Gtk::FileFilter
- * allows wildcards for the subtype of a mime type, so you can e.g. filter for image/ *.
+ * Filtering by MIME types handles aliasing and subclassing of MIME types;
+ * e.g. a filter for <tt>text/plain</tt> also matches a file with MIME type
+ * <tt>application/rtf</tt>, since <tt>application/rtf</tt> is a subclass of
+ * <tt>text/plain</tt>. Note that Gtk::FileFilter allows wildcards for the
+ * subtype of a MIME type, so you can e.g. filter for <tt>image/*</tt>.
  *
  * Normally, filters are used by adding them to a Gtk::FileChooser. See Gtk::FileChooser::add_filter().
  * But it is also possible to manually use a filter on a file with filter().