MINOR: Some spelling cleanup in the comments.

Signed-off-by: Dave Chiluk <chiluk+haproxy@indeed.com>
diff --git a/include/common/cfgparse.h b/include/common/cfgparse.h
index c003bd3..6e35bc9 100644
--- a/include/common/cfgparse.h
+++ b/include/common/cfgparse.h
@@ -92,7 +92,7 @@
 
 /*
  * Sends a warning if proxy <proxy> does not have at least one of the
- * capabilities in <cap>. An optionnal <hint> may be added at the end
+ * capabilities in <cap>. An optional <hint> may be added at the end
  * of the warning to help the user. Returns 1 if a warning was emitted
  * or 0 if the condition is valid.
  */