samples: samples:added docs links to predict samples (#3266)

Fixes #1730

Author: munkhuushmgl

automl/snippets/src/main/java/com/example/automl/LanguageEntityExtractionPredict.java

@@ -44,8 +44,14 @@ static void predict(String projectId, String modelId, String content) throws IOE
     try (PredictionServiceClient client = PredictionServiceClient.create()) {
       // Get the full path of the model.
       ModelName name = ModelName.of(projectId, "us-central1", modelId);
+
+      // For available mime types, see:
+      // https://cloud.google.com/automl/docs/reference/rest/v1/projects.locations.models/predict#textsnippet
       TextSnippet textSnippet =
-          TextSnippet.newBuilder().setContent(content).setMimeType("text/plain").build();
+          TextSnippet.newBuilder()
+                  .setContent(content)
+                  .setMimeType("text/plain") // Types: text/plain, text/html
+                  .build();
       ExamplePayload payload = ExamplePayload.newBuilder().setTextSnippet(textSnippet).build();
       PredictRequest predictRequest =
           PredictRequest.newBuilder().setName(name.toString()).setPayload(payload).build();

automl/snippets/src/main/java/com/example/automl/LanguageSentimentAnalysisPredict.java

@@ -43,6 +43,9 @@ static void predict(String projectId, String modelId, String content) throws IOE
     try (PredictionServiceClient client = PredictionServiceClient.create()) {
       // Get the full path of the model.
       ModelName name = ModelName.of(projectId, "us-central1", modelId);
+
+      // For available mime types, see:
+      // https://cloud.google.com/automl/docs/reference/rest/v1/projects.locations.models/predict#textsnippet
       TextSnippet textSnippet =
           TextSnippet.newBuilder()
               .setContent(content)

automl/snippets/src/main/java/com/example/automl/LanguageTextClassificationPredict.java

@@ -43,6 +43,9 @@ static void predict(String projectId, String modelId, String content) throws IOE
     try (PredictionServiceClient client = PredictionServiceClient.create()) {
       // Get the full path of the model.
       ModelName name = ModelName.of(projectId, "us-central1", modelId);
+
+      // For available mime types, see:
+      // https://cloud.google.com/automl/docs/reference/rest/v1/projects.locations.models/predict#textsnippet
       TextSnippet textSnippet =
           TextSnippet.newBuilder()
               .setContent(content)