syntax: sh: uncolor "tar" when it's part of a filename

syntax/sh.nanorc

@@ -13,6 +13,7 @@ color green "[{}():;|`$<>!=&\\]" "(\]|\[)"
 color green "-[Ldefgruwx]\>"
 color green "-(eq|ne|gt|lt|ge|le|s|n|z)\>"
 color brightblue "\<(awk|cat|cd|ch(grp|mod|own)|cp|cut|echo|env|grep|head|install|ln|make|mkdir|mv|popd|printf|pushd|rm|rmdir|sed|set|sort|tail|tar|touch|umask|unset)\>"
+color normal "[.-]tar\>"
 
 # Basic variable names (no braces).
 color brightred "\$[-0-9@*#?$!]" "\$[[:alpha:]_][[:alnum:]_]*"