Tiny documentation update: linetype

[Tait <gnu...@t4...>]

Just noticed that the documentation for "help linetype" says:
    ...
    For example, linetypes one and two default to red and green. If you...

This is not true anymore.

I was trying to find the colors of the default color sequence. The
sequence in "help linetype" looks plausibly correct, but it doesn't
say it's the default. "Help colorsequence" describes "podo" but
doesn't give the colors. "Show colorsequence" seems to do the same
thing as "show colors". "Show linestyle" and "show style line" just
prints a blank line. "Show linestyle 1" or "show style line 1"
report that 1 isn't a valid linestyle.

Tait