Correctly escape '<'"

Signed-off-by: Mark Thomas <markt@apache.org>

spec/src/main/asciidoc/license-efsl.adoc

@@ -28,7 +28,7 @@ document, or portions thereof, that you use:
 * All existing copyright notices, or if one does not exist, a notice
   (hypertext is preferred, but a textual representation is permitted)
   of the form: "Copyright (c) [$date-of-document]
-  Eclipse Foundation, Inc. <<url to this license>>"
+  Eclipse Foundation, Inc. \<<url to this license>>"
 
 Inclusion of the full text of this NOTICE must be provided. We
 request that authorship attribution be provided in any software,