Add USE_MEOWICE_ZGC_FLAGS to use the ZGC version of MeowIce's flags (#4382)

docs/configuration/jvm-options.md

@@ -158,3 +158,5 @@ When `MEMORY` is greater than or equal to 12G, then the Aikar flags will be adju
 [MeowIce has created an updated set of JVM flags](https://github.com/MeowIce/meowice-flags?tab=readme-ov-file#why-would-i-have-to-switch-) based on Aikar's flags but with support for optimizations for Java 17 and above
 
 The set of flags documented there can be added by setting the environment variable `USE_MEOWICE_FLAGS` to `true`. There is an optional `USE_MEOWICE_GRAALVM_FLAGS` variable to enable GraalVM specific optimizations, defaults to `FALSE`.
+
+MeowIce's flags use the G1 garbage collector by default. MeowIce also provides a [ZGC version of the flags](https://github.com/MeowIce/meowice-flags#zgc-version-for-large-servers-with-32gb-allocated-heap), which is recommended for servers with 32GB or more of allocated memory and many CPU cores. To use it instead, also set `USE_MEOWICE_ZGC_FLAGS` to `true`. When `MAX_MEMORY` (or `MEMORY`) is larger than 2GB, the soft max heap size is set to 2GB below it, as in MeowIce's flags.

docs/variables.md

@@ -129,6 +129,12 @@ alternatively, you can mount: <code>/etc/localtime:/etc/localtime:ro
             <td><code>true</code></td>
             <td>⬜️</td>
         </tr>
+        <tr>
+            <td><code>USE_MEOWICE_ZGC_FLAGS</code></td>
+            <td>uses the ZGC version of MeowIce's flags instead of the G1 version when USE_MEOWICE_FLAGS is also TRUE</td>
+            <td><code>false</code></td>
+            <td>⬜️</td>
+        </tr>
         <tr>
             <td><code>JVM_OPTS</code></td>
             <td>General JVM options can be passed to the Minecraft Server invocation by passing a <code>JVM_OPTS</code> environment variable. The JVM requires -XX options to precede -X options, so those can be declared in <code>JVM_XX_OPTS</code>. Both variables are space-delimited, raw JVM arguments</td>