Add documentations for System.Data.SqlDataReader (#3237)

* Add documentations for System.Data.SqlDataReader

* Fix minor error

* Fix for warnings

* Apply suggestions from code review

Co-Authored-By: Maira Wenzel <[email protected]>

* Fix documentation for DbDataReader and SqlDataReader classes

* Fix docs

Author: cheenamalhotra

xml/System.Data.Common/DbDataReader.xml

@@ -308,7 +308,7 @@
       <Docs>
         <param name="disposing">
           <see langword="true" /> to release managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
-        <summary>Releases the managed resources used by the <see cref="T:System.Data.Common.DbDataReader" /> and optionally releases the unmanaged resources.</summary>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Data.Common.DbDataReader" /> and optionally releases the managed resources.</summary>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   

xml/System.Data.SqlClient/SqlDataReader.xml

@@ -246,17 +246,18 @@
         <Parameter Name="disposing" Type="System.Boolean" Index="0" FrameworkAlternate="netcore-2.0;netcore-2.1;netcore-2.2;netcore-3.0" />
       </Parameters>
       <Docs>
-        <param name="disposing">
-          <see langword="true" /> to release managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
-        <summary>Releases the managed resources used by the <see cref="T:System.Data.SqlClient.SqlDataReader" /> and optionally releases the unmanaged resources.</summary>
+        <param name="disposing"><see langword="true" /> to release managed and unmanaged resources; <see langword="false" /> to release only unmanaged resources.</param>
+        <summary>Releases the unmanaged resources used by the <see cref="T:System.Data.SqlClient.SqlDataReader" /> and optionally releases the managed resources.</summary>
         <remarks>
           <format type="text/markdown"><![CDATA[
-
+              
 ## Remarks
- This method calls <xref:System.Data.SqlClient.SqlDataReader.Close%2A>.
 
-]]></format>
+This method calls <xref:System.Data.Common.DbDataReader.Dispose%2A>.
+
+  ]]></format>
         </remarks>
+        <related type="Article" href="~/docs/framework/data/adonet/ado-net-overview.md">ADO.NET Overview</related>
       </Docs>
     </Member>
     <Member MemberName="FieldCount">
@@ -664,9 +665,17 @@
       </ReturnValue>
       <Parameters />
       <Docs>
-        <summary>Gets the column schema (<see cref="T:System.Data.Common.DbColumn" /> collection).</summary>
-        <returns>The column schema (<see cref="T:System.Data.Common.DbColumn" /> collection).</returns>
-        <remarks>To be added.</remarks>
+        <summary>Gets the read-only column schema collection.</summary>
+        <returns>The read-only column schema collection.</returns>
+        <remarks>
+          <format type="text/markdown"><![CDATA[
+  
+## Remarks
+
+This method is an implementation of <xref:System.Data.Common.IDbColumnSchemaGenerator.GetColumnSchema?displayProperty=nameWithType> method, which enables the use of the <xref:System.Data.Common.IDbColumnSchemaGenerator> interface to populate the <xref:System.Data.Common.DbColumn> schema metadata without using a <xref:System.Data.DataTable>.
+
+ ]]></format>
+        </remarks>
       </Docs>
     </Member>
     <Member MemberName="GetData">