Reinstate connection width mismatch exception

[mkorbel1]

Describe the bug

When _Wires were added to ROHD Logics (#199), an exception was mistakenly removed which clearly explained why signals could not be connected when signals are different widths:

rohd/lib/src/logic.dart

Lines 261 to 264 in bae662c

	if (other.width != width) {
	throw Exception('Bus widths must match.'
	' Cannot connect $this to $other which have different widths.');
	}

We should add it back. Probably we should add a test to make sure it doesn't get removed, and also make it a unique type of exception instead of Exception. Perhaps some rewording is needed as well.

To Reproduce

Example from: #308 (reply in thread)

Expected behavior

An error something like this:

Exception: Bus widths must match. Cannot connect Logic(11): f to Logic(10): _swizzled which have different widths.

Actual behavior

Uncaught Error: Failed to put value on signal (f): Updated value width mismatch. The width of 10'bzzzz00111z should be 11

Additional: Dart SDK info

No response

Additional: pubspec.yaml

No response

Additional: Context

Present in v0.4.2