Syntax highlight more docstrings

This is going to conflict horribly with MC 1.21 (where we started using
@snippet), but hopefully this still helps.

projects/common-api/src/main/java/dan200/computercraft/api/ComputerCraftAPI.java

@@ -173,7 +173,7 @@ public final class ComputerCraftAPI {
      * This may be used with {@link IComputerSystem#getComponent(ComputerComponent)} to only attach APIs to specific
      * computers. For example, one can add an additional API just to turtles with the following code:
      *
-     * <pre>{@code
+     * <pre class="language language-java">{@code
      * ComputerCraftAPI.registerAPIFactory(computer -> {
      *   // Read the turtle component.
      *   var turtle = computer.getComponent(ComputerComponents.TURTLE);

projects/common-api/src/main/java/dan200/computercraft/api/turtle/TurtleUpgradeSerialiser.java

@@ -28,7 +28,7 @@ import java.util.function.Function;
  * {@link #simple(Function)} or {@link #simpleWithCustomItem(BiFunction)} to create a basic upgrade serialiser.
  *
  * <h2>Example (Forge)</h2>
- * <pre>{@code
+ * <pre class="language language-java">{@code
  * static final DeferredRegister<TurtleUpgradeSerialiser<?>> SERIALISERS = DeferredRegister.create( TurtleUpgradeSerialiser.TYPE, "my_mod" );
  *
  * // Register a new upgrade serialiser called "my_upgrade".
@@ -42,9 +42,9 @@ import java.util.function.Function;
  * We can then define a new upgrade using JSON by placing the following in
  * {@literal data/<my_mod>/computercraft/turtle_upgrades/<my_upgrade_id>.json}}.
  *
- * <pre>{@code
+ * <pre class="language language-json">{@code
  * {
- *     "type": my_mod:my_upgrade",
+ *     "type": "my_mod:my_upgrade",
  * }
  * }</pre>
  * <p>

projects/common-api/src/main/java/dan200/computercraft/api/upgrades/UpgradeDataProvider.java

@@ -86,7 +86,7 @@ public abstract class UpgradeDataProvider<T extends UpgradeBase, R extends Upgra
      * Add all turtle or pocket computer upgrades.
      * <p>
      * <strong>Example usage:</strong>
-     * <pre>{@code
+     * <pre class="language language-java">{@code
      * protected void addUpgrades(Consumer<Upgrade<TurtleUpgradeSerialiser<?>>> addUpgrade) {
      *     simple(new ResourceLocation("mymod", "speaker"), SPEAKER_SERIALISER.get()).add(addUpgrade);
      * }