use macro for /usr/local/plan9

man/man1/spell.1

@@ -61,10 +61,10 @@ cede to `crew member' and  `back yard' (noun) or `back-yard'
 (adjective).
 .SH FILES
 .TP
-.B /usr/local/plan9/lib/amspell
+.B \*9/lib/amspell
 American spelling list
 .TP
-.B /usr/local/plan9/lib/brspell
+.B \*9/lib/brspell
 British spelling list
 .TP
 .B /bin/aux/sprog
@@ -73,12 +73,12 @@ It expects one word per line on standard input,
 and takes the same arguments as
 .IR spell .
 .SH SOURCE
-.TF /usr/local/plan9/src/cmd/spell
+.TF \*9/src/cmd/spell
 .TP
-.B /usr/local/plan9/bin/spell
+.B \*9/bin/spell
 the script
 .TP
-.B /usr/local/plan9/src/cmd/spell
+.B \*9/src/cmd/spell
 source for
 .I sprog
 .SH SEE ALSO