Small doc update and remove obsolete TODOs

Change-Id: Ie08217d025df3ec3c97dc96268f1c4e1d20b33bf

Author: jackdingilian

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/AbstractProtoStructReader.java

@@ -316,7 +316,6 @@ private void checkNonNullOfType(
 
   private void checkNonNullOfType(
       int columnIndex, SqlType<?> expectedType, SqlType<?> actualType, Object columnNameForError) {
-    // TODO check on toString formatting
     Preconditions.checkState(
         SqlType.typesMatch(expectedType, actualType),
         "Column %s is not of correct type: expected %s but was %s",

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/EnhancedBigtableStub.java

@@ -99,6 +99,7 @@
 import com.google.cloud.bigtable.data.v2.models.RowMutationEntry;
 import com.google.cloud.bigtable.data.v2.models.SampleRowKeysRequest;
 import com.google.cloud.bigtable.data.v2.models.TargetId;
+import com.google.cloud.bigtable.data.v2.models.sql.Statement;
 import com.google.cloud.bigtable.data.v2.stub.changestream.ChangeStreamRecordMergingCallable;
 import com.google.cloud.bigtable.data.v2.stub.changestream.GenerateInitialChangeStreamPartitionsUserCallable;
 import com.google.cloud.bigtable.data.v2.stub.changestream.ReadChangeStreamResumptionStrategy;
@@ -1300,8 +1301,8 @@ public Map<String, String> extract(
    * Creates a callable chain to handle streaming ExecuteQuery RPCs. The chain will:
    *
    * <ul>
-   *   <li>Convert a {@link ExecuteQueryRequest} into a {@link ExecuteQueryCallContext}, which
-   *       passes the {@link ExecuteQueryRequest} & a future for the {@link
+   *   <li>Convert a {@link Statement} into a {@link ExecuteQueryCallContext}, which passes the
+   *       {@link Statement} & a future for the {@link
    *       com.google.cloud.bigtable.data.v2.models.sql.ResultSetMetadata} up the call chain.
    *   <li>Upon receiving the response stream, it will set the metadata future and translate the
    *       {@link com.google.bigtable.v2.PartialResultSet}s into {@link SqlRow}s
@@ -1310,7 +1311,6 @@ public Map<String, String> extract(
    *       com.google.cloud.bigtable.data.v2.stub.sql.SqlServerStream}
    * </ul>
    */
-  // TODO update docs for Statement
   @InternalApi("For internal use only")
   public ExecuteQueryCallable createExecuteQueryCallable() {
     // TODO support resumption