RE: doc string for `yank' should mention "paste"

[Drew Adams]

    The doc string for `yank' should mention the commonly understood
    "paste" operation as a (rough) synonym. Yanking is more than pasting,
    but at a first approximation they are the same thing. Users
    should be able to find `yank' when they do `M-x
    apropos-documentation paste'.

Similarly, the doc for `kill-region' should mention "cut" and the doc for
`kill-ring-save' should mention "copy".

We should provide a bridge between the vocabulary that many people are used
to and the features and vocabulary of Emacs. We make this vocabulary effort
in the Edit menu (but without bridging to the Emacs jargon); we should also
do so in the doc strings of our basic commands that are similar to commands
used in other apps.