Automatically port Collections.Immutable.ImmutableArray (#3187)

* Automatically port Collections.Immutable.ImmutableArray

* suggestions by rpetrusha

Co-Authored-By: Ron Petrusha <[email protected]>

Author: carlossanlop

xml/System.Collections.Immutable/ImmutableArray`1.xml

@@ -2749,7 +2749,7 @@
       <Docs>
         <param name="index">The index.</param>
         <summary>Gets or sets the <see cref="T:System.Object" /> at the specified index.</summary>
-        <value>To be added.</value>
+        <value>The object at the specified index.</value>
         <remarks>To be added.</remarks>
         <exception cref="T:System.NotSupportedException">Always thrown from the setter.</exception>
         <exception cref="T:System.InvalidOperationException">Thrown if the <see cref="P:System.Collections.Immutable.ImmutableArray`1.IsDefault" /> property returns true.</exception>

xml/System.Collections.Immutable/ImmutableList`1+Builder.xml

@@ -2109,7 +2109,7 @@
       <Docs>
         <param name="index">The index.</param>
         <summary>Gets or sets the <see cref="T:System.Object" /> at the specified index.</summary>
-        <value>To be added.</value>
+        <value>The object at the specified index.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>