Update documentation to contain start time of test instead of end time

I added a time column as explained in the user documentation but this adds the end timestamp.
The following seems to achieve more what I want. Some feedback would be great and maybe it is worth updating the documentation?

import pytest
from datetime import datetime


def pytest_html_results_table_header(cells):
    cells.insert(2, '<th class="sortable time" data-column-type="time">Time</th>')


def pytest_html_results_table_row(report, cells):
    start = datetime.fromtimestamp(report.start)
    cells.insert(2, f'<td class="col-time">{start}</td>')


@pytest.hookimpl(hookwrapper=True)
def pytest_runtest_makereport(item, call):
    outcome = yield
    report = outcome.get_result()
    report.start = call.start

I am still a bit unsure about the different phases of a test like setup, call and teardown. Maybe this needs extra handling?

Start with the user documentation section describing the time column and compare it with the pytest hooks and HTML cells shown in the issue. Check how setup, call, and teardown phases are represented, then update the documentation so the intended timestamp behavior is explicit and verify the example remains accurate.