Possible Godoc improvements

[acln0]

I think https://godoc.org/github.com/gofrs/uuid#Equal should say "Nil is the nil UUID...".

https://godoc.org/github.com/gofrs/uuid#UUID.UnmarshalText should mention the braced hashlike format, as described in #14, and the URN hashlike format as in

uuid/codec_test.go

Lines 131 to 134 in 57be146

	{
	input: "urn:uuid:6ba7b8109dad11d180b400c04fd430c8",
	variant: "URNHashlike",
	},

.

Perhaps https://godoc.org/github.com/gofrs/uuid#DefaultGenerator could be placed outside the var block it is currently in, standing alone instead, to reduce noise and to promote the comment to a "proper Godoc" rather than code comment.

Perhaps the comment on https://godoc.org/github.com/gofrs/uuid#UUID could also be improved. It feels like it needs a verb.