[pgf-tikz] Spotted typos in PGF/TiKZ manual

[Justus Greve-Kramer]

Hello,

I think I have spotted minor errors in the documentation of the TikZ
package.

- In "Karl's tutorial" in section 2.2.1, it says: The first path is
specified as (-1.5,0)--(0,1.5), which means “a straight line from the
point at position (−1.5, 0) to the point at position (0, 1.5)”.
But in fact, the second position should be (1.5,0) (in both places).

- In section 2.10, it says: For this, he can add the [scale=3 option.
Maybe it's intentional, but for me the missing closing bracket or the
needless opening bracket is irritating.

- It becomes apparent that the author likes not to receive undiscerning
emails. But even more, I think that the manual contains no contact email
address. I suggest putting some contact info somewhere in the manual
where one would find it if they were looking for it. (As of writing this
email, I am not completely sure whether the recipient list was a correct
choice.)

Thanks for maintaining this package!