Re: Lowercase "arg" in doc strings.

[Richard Stallman]

    -With prefix arg, kill that many lines starting from the current line.
    -If arg is negative, kill backward.  Also kill the preceding newline,
    +With prefix ARG, kill that many lines starting from the current line.

Using ARG in upper case in this doc string is a good change, but it's
not correct to say "prefix ARG", because that implies ARG is a prefix.
It isn't a prefix, it is a prefix argument (often abbreviated "prefix
arg").

If you change that to "With prefix arg ARG", then it would be correct.
However, it might be clearer overall if you replace ARG with COUNT or N.

    -With arg, set read-only iff arg is positive.
    +With ARG, set read-only iff ARG is positive.

The current text makes sense; it is a terse way of saying "with a
prefix argument".  The proposed changed text does not make sense.  You
need to do this some other way.

In general, "arg" is an English noun, an abbreviation of "argument".
"ARG" is a proper name, the name of one particular argument.  They do
not have the same meaning, and they cannot be used in the same
contexts, so you cannot just replace one with the other.  To make the
text use ARG, you need to rewrite it so that it makes sense and still
says the other things it needs to say.