Document `from_name` parameter for `connect` method

[akalsey]

The from_name parameter is a valid, functional parameter for the SWML connect method that controls the caller ID name sent with the call. It works when used but is completely absent from the documentation at https://developer.signalwire.com/swml/methods/connect.

Beyond simply adding the parameter, the documentation should explain how caller ID name actually works in telephony, since the behavior is non-obvious and will lead to developer confusion:

• PSTN calls: The from_name value is generally ignored by the receiving carrier. Caller ID name (CNAM) on traditional phone calls is determined by a carrier-side database lookup (CNAM dip) based on the calling number, not by any value the originating party sends. The parameter has no practical effect in most PSTN scenarios.
• Mobile calls: The handset contact list / phone book overrides any network-provided caller ID name.
• SIP-to-SIP calls: from_name is useful here, as the value is passed through and typically displayed by the receiving SIP endpoint.
• Limited VoIP scenarios: Some VoIP phones and softphones will display the provided name when no local contact match exists.

Without this context, developers will set from_name, see it ignored on PSTN test calls, and assume it's broken — or worse, rely on it for user-facing display and ship a broken experience.