Merge pull request dotnet#4844 from eiriktsarpalis/system-collections-docs

Add missing System.Collections api docs

Author: eiriktsarpalis

xml/System.Collections.Generic/KeyValuePair.xml

@@ -24,7 +24,7 @@
  </Base>
  <Interfaces />
  <Docs>
- <summary>To be added.</summary>
+ <summary>Creates instances of the <see cref="T:System.Collections.Generic.KeyValuePair`2" /> struct.</summary>
  <remarks>To be added.</remarks>
  </Docs>
  <Members>
@@ -60,12 +60,12 @@
  <Parameter Name="value" Type="TValue" />
  </Parameters>
  <Docs>
- <typeparam name="TKey">To be added.</typeparam>
- <typeparam name="TValue">To be added.</typeparam>
- <param name="key">To be added.</param>
- <param name="value">To be added.</param>
- <summary>To be added.</summary>
- <returns>To be added.</returns>
+ <typeparam name="TKey">The type of the key.</typeparam>
+ <typeparam name="TValue">The type of the value.</typeparam>
+ <param name="key">The key of the new <see cref="T:System.Collections.Generic.KeyValuePair`2" /> to be created.</param>
+ <param name="value">The value of the new <see cref="T:System.Collections.Generic.KeyValuePair`2" /> to be created.</param>
+ <summary>Creates a new key/value pair instance using provided values.</summary>
+ <returns>A key/value pair containing the provided arguments as values.</returns>
  <remarks>To be added.</remarks>
  </Docs>
  </Member>

xml/System.Collections.Generic/LinkedListNode`1.xml

@@ -361,8 +361,8 @@
  <ReturnType>T</ReturnType>
  </ReturnValue>
  <Docs>
- <summary>To be added.</summary>
- <value>To be added.</value>
+ <summary>Gets a reference to the value held by the node.</summary>
+ <value>A reference to the value held by the node.</value>
  <remarks>To be added.</remarks>
  </Docs>
  </Member>