API: Correct documentation of String::WriteUtf8, String::Write...

include/v8.h

Index: include/v8.h
===================================================================
--- include/v8.h	(revision 5999)
+++ include/v8.h	(working copy)
@@ -992,18 +992,23 @@
    * the contents of the string and the NULL terminator into the
    * buffer.
    *
+   * WriteUtf8 will not write partial UTF-8 sequences, preferring to stop
+   * before the end of the buffer.
+   *
    * Copies up to length characters into the output buffer.
    * Only null-terminates if there is enough space in the buffer.
    *
    * \param buffer The buffer into which the string will be copied.
    * \param start The starting position within the string at which
    * copying begins.
-   * \param length The number of bytes to copy from the string.
+   * \param length The number of characters to copy from the string.  For
+   *    WriteUtf8 the number of bytes in the buffer.
    * \param nchars_ref The number of characters written, can be NULL.
    * \param hints Various hints that might affect performance of this or
    *    subsequent operations.
-   * \return The number of bytes copied to the buffer
-   * excluding the NULL terminator.
+   * \return The number of characters copied to the buffer excluding the null
+   *    terminator.  For WriteUtf8: The number of bytes copied to the buffer
+   *    including the null terminator.
    */
   enum WriteHints {
     NO_HINTS = 0,