docs: Remove escaping '\' from literals

commit 35066ed6c6 replaced entities, but
escaped the replacement text also inside literals, which resulted in the
escaping '\' to also appear in the documentation.

https://bugzilla.gnome.org/show_bug.cgi?id=727320

gio/gappinfo.c

@@ -41,7 +41,7 @@
  * (using g_file_get_path()) when using g_app_info_launch() even if
  * the application requested an URI and not a POSIX path. For example
  * for an desktop-file based application with Exec key `totem
- * \%U` and a single URI, `sftp://foo/file.avi`, then
+ * %U` and a single URI, `sftp://foo/file.avi`, then
  * `/home/user/.gvfs/sftp on foo/file.avi` will be passed. This will
  * only work if a set of suitable GIO extensions (such as gvfs 2.26
  * compiled with FUSE support), is available and operational; if this

gio/gicon.c

@@ -197,7 +197,7 @@ g_icon_to_string_tokenized (GIcon *icon, GString *s)
  *   (such as `/path/to/my icon.png`) without escaping
  *   if the #GFile for @icon is a native file.  If the file is not
  *   native, the returned string is the result of g_file_get_uri()
- *   (such as `sftp://path/to/my\%20icon.png`).
+ *   (such as `sftp://path/to/my%20icon.png`).
  * 
  * - If @icon is a #GThemedIcon with exactly one name, the encoding is
  *    simply the name (such as `network-server`).