[SPARK-32234][FOLLOWUP][SQL] Update the description of utility method

### What changes were proposed in this pull request?
As the part of this PR #29045 added the helper method. This PR is the FOLLOWUP PR to update the description of helper method.

### Why are the changes needed?
For better readability and understanding of the code

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
Since its only change of updating the description , So ran the Spark shell

Closes #29232 from SaurabhChawla100/SPARK-32234-Desc.

Authored-by: SaurabhChawla <s.saurabhtim@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>

sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/orc/OrcUtils.scala

@@ -207,10 +207,16 @@ object OrcUtils extends Logging {
   }
 
   /**
-   * @return Returns the result schema string based on the canPruneCols flag.
-   *         resultSchemaString will be created using resultsSchema in case of
-   *         canPruneCols is true and for canPruneCols as false value
-   *         resultSchemaString will be created using the actual dataSchema.
+   * Returns the result schema to read from ORC file. In addition, It sets
+   * the schema string to 'orc.mapred.input.schema' so ORC reader can use later.
+   *
+   * @param canPruneCols Flag to decide whether pruned cols schema is send to resultSchema
+   *                     or to send the entire dataSchema to resultSchema.
+   * @param dataSchema   Schema of the orc files.
+   * @param resultSchema Result data schema created after pruning cols.
+   * @param partitionSchema Schema of partitions.
+   * @param conf Hadoop Configuration.
+   * @return Returns the result schema as string.
    */
   def orcResultSchemaString(
       canPruneCols: Boolean,