Remove outdated comments about expanduser and expandvars for Macintosh that

referred to OS 9 semantics.

Doc/lib/libposixpath.tex

@@ -61,8 +61,7 @@ initial \samp{\~{}} is replaced by the environment variable
 \envvar{HOME}; an initial \samp{\~\var{user}} is looked up in the
 password directory through the built-in module
 \refmodule{pwd}\refbimodindex{pwd}.  If the expansion fails, or if the
-path does not begin with a tilde, the path is returned unchanged.  On
-the Macintosh, this always returns \var{path} unchanged.
+path does not begin with a tilde, the path is returned unchanged.
 \end{funcdesc}
 
 \begin{funcdesc}{expandvars}{path}
@@ -70,7 +69,6 @@ Return the argument with environment variables expanded.  Substrings
 of the form \samp{\$\var{name}} or \samp{\$\{\var{name}\}} are
 replaced by the value of environment variable \var{name}.  Malformed
 variable names and references to non-existing variables are left
-unchanged.  On the Macintosh, this always returns \var{path}
 unchanged.
 \end{funcdesc}