Cookies.set() should prepend a period to the domain

[ppena-LiveData]

Since httpx._models.Cookies uses http.cookiejar, Cookies.set() should check if the passed-in domain has a leading period, and if not, it should prepend a period. When there is no leading period for the cookie's domain, then cookiejar.CookieJar.clear() cannot delete the cookie, and since prepending a period is not really intuitive, httpx._models.Cookies should do that for the user.

For those wondering, cookiejar.CookieJar.clear() just does a del self._cookies[domain][path][name], so the domain has to match exactly, and this code that calls it is the thing that adds the period to the web response's cookie domain right before CookieJar.clear() is called.

[tomchristie]

Could you give us an example...

[ppena-LiveData]

Sorry, upon further review, it looks like it's really an http.cookiejar issue, so I'll file the bug with them instead.

python/cpython#108931