Add isLoaded() and isSaved() to HashStore

A use case of `isSaved()` could be to throw an exception of the hash
store is expected to be saved after usage when it isn't.

Author: Jonathing

hash-utils/src/main/java/net/minecraftforge/util/hash/HashStore.java

@@ -28,6 +28,7 @@ public class HashStore {
     private final Map<String, String> oldHashes = new HashMap<>();
     private final Map<String, String> newHashes = new HashMap<>();
     private @Nullable File target;
+    private boolean saved;
 
     public static HashStore fromFile(File path) {
         File parent = path.getAbsoluteFile().getParentFile();
@@ -106,6 +107,10 @@ public HashStore load(File file) {
         return this;
     }
 
+    public boolean isLoaded() {
+        return this.target != null;
+    }
+
     public boolean exists() {
         return this.target != null && this.target.exists();
     }
@@ -193,11 +198,16 @@ public void save(File file) {
 
         try {
             Files.write(file.toPath(), buf.toString().getBytes(StandardCharsets.UTF_8));
+            this.saved = true;
         } catch (IOException e) {
             sneak(e);
         }
     }
 
+    public boolean isSaved() {
+        return this.saved;
+    }
+
     private String getPath(File file) {
         String path = file.getAbsolutePath();