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/getsid.c

@@ -23,7 +23,7 @@
 /**
  * Creates session and sets the process group id.
  */
-uint32_t getsid(int pid) {
+int getsid(int pid) {
   int rc;
   rc = sys_getsid(pid);
   STRACE("%s(%d) → %d% m", "getsid", pid, rc);