Correct unicode range in legal title regular expression

The old regex was lifted from PHP, which matches on UTF-8 byte sequences.
In PHP, [...\x80-\xFF]+ matches any bytes with the high bit set, which
by the particular properties of UTF-8 will match any sequence which
represents a Unicode character above U+007F.

In Javascript, regex matching is on UTF-16 Unicode code units, so we
don't have to do byte sequence matching (and cannot do so). So the
equivalent Javascript regex should use [...\u0080-\uFFFF]+, to match any
code unit above U+007F directly. (It also matches surrogate pairs, by
the particular properties of UTF-16, so any Unicode codepoint above
U+007F is matched).

Change-Id: I674b89f757b60331dd1cb23fd7ff8b18775012e9
Merge "Correct unicode range in legal title regular expression"