docs: Link to curl's redistribution of Mozilla's CA bundle (#13663)

While we would hope that people aren't using Python
installations that need a separate CA bundle, we can
provide a link to the curl's extraction of the
Mozilla CA bundle (apparently it's extracted from the
latest build of Firefox, hence its name).

Co-authored-by: Richard Si <[email protected]>

Author: Hasan-8326

docs/html/topics/https-certificates.md

@@ -17,6 +17,9 @@ allow users to specify a different certificate store/bundle for pip to use. It
 is also possible to use `REQUESTS_CA_BUNDLE` or `CURL_CA_BUNDLE` environment
 variables.
 
+If you need a specific certificate bundle, you can download the
+[Mozilla CA bundle provided by the curl project](https://curl.se/docs/caextract.html).
+
 ## Using system certificate stores
 
 ```{versionadded} 24.2