Fix Javadoc typo

Closes gh-1531

Author: xavier630

spring-context/src/main/java/org/springframework/validation/Errors.java

@@ -172,7 +172,7 @@ void rejectValue(@Nullable String field, String errorCode,
 	/**
 	 * Add all errors from the given {@code Errors} instance to this
 	 * {@code Errors} instance.
-	 * <p>This is a onvenience method to avoid repeated {@code reject(..)}
+	 * <p>This is a convenience method to avoid repeated {@code reject(..)}
 	 * calls for merging an {@code Errors} instance into another
 	 * {@code Errors} instance.
 	 * <p>Note that the passed-in {@code Errors} instance is supposed