[BOLT] Use StringRef::contains (NFC) (#92842)

Author: kazutakahirata

bolt/lib/Profile/DataAggregator.cpp

@@ -1227,7 +1227,7 @@ ErrorOr<Location> DataAggregator::parseLocationOrOffset() {
   if (Sep == StringRef::npos)
     return parseOffset();
   StringRef LookAhead = ParsingBuf.substr(0, Sep);
-  if (LookAhead.find_first_of(":") == StringRef::npos)
+  if (!LookAhead.contains(':'))
     return parseOffset();
 
   ErrorOr<StringRef> BuildID = parseString(':');