Make improvements

- Expand redbean UNIX module
- Expand redbean documentation
- Ensure Lua copyright is embedded in binary
- Increase the PATH_MAX limit especially on NT
- Use column major sorting for linenoise completions
- Fix some suboptimalities in redbean's new UNIX API
- Figured out right flags for Multics newline in raw mode

libc/calls/fileexists.c

@@ -48,7 +48,7 @@ bool fileexists(const char *path) {
   bool res;
   union metastat st;
   struct ZiposUri zipname;
-  uint16_t path16[PATH_MAX];
+  uint16_t path16[PATH_MAX + 1];
   e = errno;
   if (IsAsan() && !__asan_is_valid(path, 1)) {
     efault();