Add InlineArrayAttribute docs (#9600)

Author: gewarren

xml/System.Runtime.CompilerServices/InlineArrayAttribute.xml

@@ -25,7 +25,16 @@
   </Attributes>
   <Docs>
     <summary>Indicates that the instance's storage is sequentially replicated <see cref="P:System.Runtime.CompilerServices.InlineArrayAttribute.Length" /> times.</summary>
-    <remarks>To be added.</remarks>
+    <remarks>This attribute can be used to annotate a <see langword="struct"/> type with a single field. The runtime replicates that field in the actual type layout as many times as is specified.</remarks>
+    <example>The following example shows how to declare an inline array type with eight <see langword="float"/> values.
+      <code lang="csharp">
+      [InlineArray(8)]
+      struct Float8InlineArray
+      {
+          private float _value;
+      }
+      </code>
+    </example>
   </Docs>
   <Members>
     <Member MemberName=".ctor">
@@ -44,8 +53,8 @@
         <Parameter Name="length" Type="System.Int32" />
       </Parameters>
       <Docs>
-        <param name="length">To be added.</param>
-        <summary>To be added.</summary>
+        <param name="length">The number of sequential fields to replicate in the inline array type.</param>
+        <summary>Creates a new <see cref="T:System.Runtime.CompilerServices.InlineArrayAttribute" /> instance with the specified length.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
@@ -65,8 +74,8 @@
         <ReturnType>System.Int32</ReturnType>
       </ReturnValue>
       <Docs>
-        <summary>To be added.</summary>
-        <value>To be added.</value>
+        <summary>Gets the number of sequential fields to replicate in the inline array type.</summary>
+        <value>The number of sequential fields to replicate in the inline array type.</value>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>