[RFAv2 3/4] Update tests following changes to "help" and "apropos"

[Tom Tromey]

>>>>> "Philippe" == Philippe Waroquiers <philippe.waroquiers@skynet.be> writes:

Philippe> Factorizes the testing of the help output, by having a single place
Philippe> that defines the common help trailer and/or prefix messages.

Thank you for doing this.  This is ok.

Tom