Bring Lua to 5.4.6. (#1214)

This essentially re-does the work of #875 on top of master.

This is what I did to check that Cosmo's Lua extensions still worked:

```
$ build/bootstrap/make MODE=aarch64 o/aarch64/third_party/lua/lua
$ ape o/aarch64/third_party/lua/lua
>: 10
10
>: 010
8
>: 0b10
2
>: string.byte("\e")
27
>: "Hello, %s" % {"world"}
Hello, world
>: "*" * 3
***
```

`luaL_traceback2` was used to show the stack trace with parameter
values; it's used in `LuaCallWithTrace`, which is used in Redbean to run
Lua code. You should be able to see the extended stack trace by running
something like this: `redbean -e "function a(b)c()end a(2)"` (with
"params" indicating the extended stack trace):

```
stack traceback:
 [string "function a(b)c()end a(2)"]:1: in function 'a', params: b = 2;
 [string "function a(b)c()end a(2)"]:1: in main chunk
```
@pkulchenko confirmed that I get the expected result with the updated
code.

This is what I did to check that Lua itself still worked:

```
$ cd third_party/lua/test/
$ ape ../../../o/aarch64/third_party/lua/lua all.lua
```

There's one test failure, in `files.lua`:

```
***** FILE 'files.lua'*****
testing i/o
../../../o/aarch64/third_party/lua/lua: files.lua:84: assertion failed!
stack traceback:
[C]: in function 'assert'
files.lua:84: in main chunk
(...tail calls...)
all.lua:195: in main chunk
[C]: in ?
.>>> closing state <<<
```

That isn't a result of these changes; the same test is failing in
master.

The failure is here:

```lua
if not _port then   -- invalid seek
  local status, msg, code = io.stdin:seek("set", 1000)
  assert(not status and type(msg) == "string" and type(code) == "number")
end
```

The test expects a seek to offset 1,000 on stdin to fail — but it
doesn't. `status` ends up being the new offset rather than `nil`.

If I comment out that one test, the remaining tests succeed.

third_party/lua/llex.c

@@ -3,7 +3,7 @@
 ╚──────────────────────────────────────────────────────────────────────────────╝
 │                                                                              │
 │  Lua                                                                         │
-│  Copyright © 2004-2021 Lua.org, PUC-Rio.                                     │
+│  Copyright © 2004-2023 Lua.org, PUC-Rio.                                     │
 │                                                                              │
 │  Permission is hereby granted, free of charge, to any person obtaining       │
 │  a copy of this software and associated documentation files (the             │
@@ -27,6 +27,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #define llex_c
 #define LUA_CORE
+
 #include "third_party/lua/llex.h"
 #include "third_party/lua/lctype.h"
 #include "third_party/lua/ldebug.h"
@@ -142,7 +143,7 @@ l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
 ** ensuring there is only one copy of each unique string.  The table
 ** here is used as a set: the string enters as the key, while its value
 ** is irrelevant. We use the string itself as the value only because it
-** is a TValue readly available. Later, the code generation can change
+** is a TValue readily available. Later, the code generation can change
 ** this value.
 */
 TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
@@ -152,12 +153,12 @@ TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
   if (!ttisnil(o))  /* string already present? */
     ts = keystrval(nodefromval(o));  /* get saved copy */
   else {  /* not in use yet */
-    TValue *stv = s2v(L->top++);  /* reserve stack space for string */
+    TValue *stv = s2v(L->top.p++);  /* reserve stack space for string */
     setsvalue(L, stv, ts);  /* temporarily anchor the string */
     luaH_finishset(L, ls->h, stv, o, stv);  /* t[string] = string */
     /* table is not a metatable, so it does not need to invalidate cache */
     luaC_checkGC(L);
-    L->top--;  /* remove string from stack */
+    L->top.p--;  /* remove string from stack */
   }
   return ts;
 }
@@ -408,9 +409,9 @@ static void read_string (LexState *ls, int del, SemInfo *seminfo) {
         int c;  /* final character to be saved */
         save_and_next(ls);  /* keep '\\' for error messages */
         switch (ls->current) {
-          case 'e': c = '\e'; goto read_save;
           case 'a': c = '\a'; goto read_save;
           case 'b': c = '\b'; goto read_save;
+          case 'e': c = '\e'; goto read_save;  // [jart]
           case 'f': c = '\f'; goto read_save;
           case 'n': c = '\n'; goto read_save;
           case 'r': c = '\r'; goto read_save;