arrow

GH-35770: [Go][Documentation] Update TimestampType zero value as seconds in comment (#37905)

### Rationale for this change

To clear the confusion around the zero value of `TimestampType`

### What changes are included in this PR?

Just a comment change `nanosecond -> second`

### Are these changes tested?

No need to test

### Are there any user-facing changes?

No

Closes: https://github.com/apache/arrow/issues/35770
* Closes: #35770

Authored-by: ismail simsek <ismailsimsek09@gmail.com>
Signed-off-by: Matt Topol <zotthewizard@gmail.com>