Generate files for multiple versions

tl;dr:

replace

```php
$function_list = read_docs();
generate_files($function_list, "../generated/");
```

with

```php
foreach(["8.1", "8.2", "8.3", "8.4"] as $version) {
    exec("cd docs && git checkout $version");
    $function_list = read_docs();
    generate_files($function_list, "../generated/$version/");
}
```

generate a bunch of stubs like generated/misc.php:

```php
<?php
if(PHP_VERSION == "8.1") require_once __DIR__ . "/8.1/misc.php";
if(PHP_VERSION == "8.2") require_once __DIR__ . "/8.2/misc.php";
if(PHP_VERSION == "8.3") require_once __DIR__ . "/8.3/misc.php";
if(PHP_VERSION == "8.4") require_once __DIR__ . "/8.4/misc.php";
```

This also automates generation of "deprecated" `safe` functions (ie, instead of hard-coding `deprecated/apache.php`, any functions which were generated in `8.1/apache.php` but are no longer needed and thus not-generated in `8.2/apache.php` will end up in `8.2/deprecated.php`. Perhaps it'd be better to put them at the tail of `8.2/apache.php`? PRs welcome)

Currently the `Exceptions` are shared between all versions, which I _think_ is a good idea? (Thoughts, anybody?)

This isn't even remotely tested, just a proof of concept to show what this kind of approach might look like

composer.json

@@ -7,21 +7,10 @@
             "lib/DateTime.php",
             "lib/DateTimeImmutable.php",
             "lib/Exceptions/",
-            "deprecated/Exceptions/",
             "generated/Exceptions/"
         ],
         "files": [
-            "deprecated/apc.php",
-            "deprecated/array.php",
-            "deprecated/datetime.php",
-            "deprecated/libevent.php",
-            "deprecated/misc.php",
-            "deprecated/password.php",
-            "deprecated/mssql.php",
-            "deprecated/stats.php",
-            "deprecated/strings.php",
             "lib/special_cases.php",
-            "deprecated/mysqli.php",
             "generated/apache.php",
             "generated/apcu.php",
             "generated/array.php",
@@ -43,6 +32,7 @@
             "generated/ftp.php",
             "generated/funchand.php",
             "generated/gettext.php",
+            "generated/gmp.php",
             "generated/gnupg.php",
             "generated/hash.php",
             "generated/ibase.php",
@@ -60,6 +50,7 @@
             "generated/mbstring.php",
             "generated/misc.php",
             "generated/mysql.php",
+            "generated/mysqli.php",
             "generated/network.php",
             "generated/oci8.php",
             "generated/opcache.php",
@@ -72,7 +63,6 @@
             "generated/ps.php",
             "generated/pspell.php",
             "generated/readline.php",
-            "generated/rnp.php",
             "generated/rpminfo.php",
             "generated/rrd.php",
             "generated/sem.php",
@@ -98,7 +88,8 @@
             "generated/yaml.php",
             "generated/yaz.php",
             "generated/zip.php",
-            "generated/zlib.php"
+            "generated/zlib.php",
+            "generated/rnp.php"
         ]
     },
     "require": {