Add missing docs

Author: freya022

api/src/main/java/dev/freya02/discord/zstd/api/DiscordZstd.java

@@ -4,6 +4,10 @@
 
 import java.io.InputStream;
 
+/**
+ * Main interface which allows creating {@linkplain DiscordZstdContext decompression contexts},
+ * and {@linkplain DiscordZstdDecompressorFactory decompressor factories}.
+ */
 @NullMarked
 public interface DiscordZstd {
     /**
@@ -20,7 +24,7 @@ public interface DiscordZstd {
      * @param  bufferSizeHint
      *         A hint for the size of the buffer used for decompression,
      *         must be larger than {@value DiscordZstdDecompressor#MIN_BUFFER_SIZE} or be equal to {@value DiscordZstdDecompressor#ZSTD_RECOMMENDED_BUFFER_SIZE}.
-     *         Typically, bigger buffers mean less decompression loops, it does not change inputs or outputs
+     *         <br>Typically, bigger buffers mean less decompression loops, it does not change inputs or outputs
      *
      * @throws IllegalArgumentException
      *         If {@code bufferSize} is less than {@value DiscordZstdDecompressor#MIN_BUFFER_SIZE} and not {@value DiscordZstdDecompressor#ZSTD_RECOMMENDED_BUFFER_SIZE}

api/src/main/java/dev/freya02/discord/zstd/api/DiscordZstdContext.java

@@ -4,11 +4,45 @@
 
 import java.io.InputStream;
 
+/**
+ * Wraps a Zstandard decompression context, it keeps track of the previous decompressed data,
+ * allowing for greater compression ratios, but the data must be decompressed in the same order.
+ *
+ * <br>It can be used to decompress-as-you-consume with {@link InputStream InputStreams}.
+ *
+ * <p>Instances are <b>not</b> thread safe.
+ */
 @NullMarked
 public interface DiscordZstdContext {
+    /**
+     * Closes the context and frees resources.
+     *
+     * <p>If this is already closed, this is a no-op.
+     */
     void close();
 
+    /**
+     * Resets the current context so it can be used again.
+     *
+     * @throws IllegalStateException
+     *         If the context is closed
+     */
     void reset();
 
+    /**
+     * Exceptions thrown by the {@link InputStream} will invalidate the decompression context,
+     * in which case you will need to recreate a new one or call {@link #reset()},
+     * as well as recreate a gateway connection.
+     *
+     * @param  input
+     *         The data to decompress
+     *
+     * @throws IllegalArgumentException
+     *         If the provided input is {@code null}
+     * @throws IllegalStateException
+     *         If the context is closed or in an errored state
+     *
+     * @return The new {@link InputStream}
+     */
     InputStream createInputStream(byte[] input);
 }

api/src/main/java/dev/freya02/discord/zstd/api/DiscordZstdProvider.java

@@ -6,6 +6,9 @@
 import java.util.ServiceConfigurationError;
 import java.util.ServiceLoader;
 
+/**
+ * Entrypoint of {@code discord-zstd-java}. This is where you can get instances of {@link DiscordZstd}.
+ */
 @NullMarked
 public class DiscordZstdProvider {