lib: CURLOPT_HAPPY_EYEBALLS_TIMEOUT => CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS

- In keeping with the naming of our other connect timeout options rename
  CURLOPT_HAPPY_EYEBALLS_TIMEOUT to CURLOPT_HAPPY_EYEBALLS_TIMEOUT_MS.

This change adds the _MS suffix since the option expects milliseconds.
This is more intuitive for our users since other connect timeout options
that expect milliseconds use _MS such as CURLOPT_TIMEOUT_MS,
CURLOPT_CONNECTTIMEOUT_MS, CURLOPT_ACCEPTTIMEOUT_MS.

The tool option already uses an -ms suffix, --happy-eyeballs-timeout-ms.

Follow-up to 2427d94c which added the lib and tool option yesterday.

Ref: https://github.com/curl/curl/pull/2260