Typo

Fixes https://github.com/harfbuzz/harfbuzz/issues/711

util/options.cc

diff --git a/util/options.cc b/util/options.cc
index f4ac445..d9486f8 100644
--- a/util/options.cc
+++ b/util/options.cc
@@ -546,7 +546,7 @@
   };
   parser->add_group (entries2,
 		     "variations",
-		     "Varitions options:",
+		     "Variations options:",
 		     "Options for font variations used",
 		     this);
 }