TextFormat extension printing fix.

If a proto has multiple extension ranges back to back, don't double
print the first items as they also are the ending range of the
previous.
diff --git a/objectivec/GPBUtilities.m b/objectivec/GPBUtilities.m
index 72b5135..0d3a080 100644
--- a/objectivec/GPBUtilities.m
+++ b/objectivec/GPBUtilities.m
@@ -1865,7 +1865,7 @@
       // Not there yet.
       continue;
     }
-    if (fieldNumber > end) {
+    if (fieldNumber >= end) {
       // Done.
       break;
     }