improve docs

src/main/java/org/stellar/sdk/TransactionBuilder.java

@@ -263,7 +263,13 @@ public static org.stellar.sdk.xdr.TimeBounds buildTimeBounds(long minTime, long
   }
 
   /**
-   * Sets Soroban data to the transaction. TODO: After adding SorobanServer, add more descriptions.
+   * Sets the transaction's internal Soroban transaction data (resources, footprint, etc.).
+   *
+   * <p>For non-contract(non-Soroban) transactions, this setting has no effect. In the case of
+   * Soroban transactions, this is either an instance of {@link SorobanTransactionData} or a
+   * base64-encoded string of said structure. This is usually obtained from the simulation response
+   * based on a transaction with a Soroban operation (e.g. {@link InvokeHostFunctionOperation},
+   * providing necessary resource and storage footprint estimations for contract invocation.
    *
    * @param sorobanData Soroban data to set
    * @return Builder object so you can chain methods.
@@ -274,7 +280,13 @@ public TransactionBuilder setSorobanData(SorobanTransactionData sorobanData) {
   }
 
   /**
-   * Sets Soroban data to the transaction. TODO: After adding SorobanServer, add more descriptions.
+   * Sets the transaction's internal Soroban transaction data (resources, footprint, etc.).
+   *
+   * <p>For non-contract(non-Soroban) transactions, this setting has no effect. In the case of
+   * Soroban transactions, this is either an instance of {@link SorobanTransactionData} or a
+   * base64-encoded string of said structure. This is usually obtained from the simulation response
+   * based on a transaction with a Soroban operation (e.g. {@link InvokeHostFunctionOperation},
+   * providing necessary resource and storage footprint estimations for contract invocation.
    *
    * @param sorobanData Soroban data to set
    * @return Builder object so you can chain methods.