ICU-10088 Fix incorrect API doc for uregex_setStackLimit().

X-SVN-Rev: 33854
diff --git a/icu4c/source/i18n/unicode/uregex.h b/icu4c/source/i18n/unicode/uregex.h
index e0007fe..a85ba12 100644
--- a/icu4c/source/i18n/unicode/uregex.h
+++ b/icu4c/source/i18n/unicode/uregex.h
@@ -1431,8 +1431,8 @@
  * <p>
  * @param   regexp      The compiled regular expression.
  * @param   limit       The maximum size, in bytes, of the matching backtrack stack.
- *                      A value of -1 means no limit.
- *                      The limit must be greater than zero, or -1.
+ *                      A value of zero means no limit.
+ *                      The limit must be greater than or equal to zero.
  * @param   status      A reference to a UErrorCode to receive any errors.
  *
  * @stable ICU 4.0