"""Calculate and format summary statistics for a time series.

This function computes key statistical measures (count, maximum, minimum, mean, and median) for a given time series and formats the results into a markdown string. If the input time series is empty, it returns a message indicating no data points.

Args:
    ts (list): List of numeric values representing a time series.

Returns:
    str: Markdown formatted string containing summary statistics. If the input list is empty, returns "No data points".
"""
You should write code starting with:
import statistics

def _timeseries_stats(ts: list) -> str:
    # TODO: Implement this function
    pass

