[latexrefman] Suggestion for update url links

[Pablo González L]

Hello everyone, just as a suggestion (for a future update), many of the
links described are in the form `http` and can be updated to `https`.
It's not that they are broken, it's just that some browsers complain
that the `s` isn't there.

Saludos

PS: I have some other suggestions regarding changes described in ltnews
that maybe can be added, but, I don't want to abuse the time :) I will
send them separately.