Minor updates (#10547)

* System.Collections.Concurrent

* System.Collections.Generic

* System.IO.Compression

xml/System.Collections.Concurrent/ConcurrentDictionary`2.xml

@@ -1416,7 +1416,7 @@
       <Docs>
         <summary>Gets a collection containing the keys in the <see cref="T:System.Collections.Generic.Dictionary`2" />.</summary>
         <value>A collection of keys in the <see cref="T:System.Collections.Generic.Dictionary`2" />.</value>
-        <remarks>To be added.</remarks>
+        <remarks>The property returns a copy of all the keys. It's not kept in sync with <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" />.</remarks>
         <related type="Article" href="/dotnet/standard/collections/thread-safe/">Thread-Safe Collections</related>
         <related type="Article" href="/dotnet/standard/collections/thread-safe/how-to-add-and-remove-items">How to: Add and Remove Items from a ConcurrentDictionary</related>
       </Docs>
@@ -3003,7 +3003,7 @@ The key is compared using the dictionary's comparer (or the default comparer for
       <Docs>
         <summary>Gets a collection that contains the values in the <see cref="T:System.Collections.Generic.Dictionary`2" />.</summary>
         <value>A collection that contains the values in the <see cref="T:System.Collections.Generic.Dictionary`2" />.</value>
-        <remarks>To be added.</remarks>
+        <remarks>The property returns a copy of all the values. It's not kept in sync with <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" />.</remarks>
         <related type="Article" href="/dotnet/standard/collections/thread-safe/">Thread-Safe Collections</related>
         <related type="Article" href="/dotnet/standard/collections/thread-safe/how-to-add-and-remove-items">How to: Add and Remove Items from a ConcurrentDictionary</related>
       </Docs>

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

@@ -1310,9 +1310,10 @@ The following example demonstrates how to merge two disparate sets. This example
       <Parameters />
       <Docs>
         <typeparam name="TAlternate">The alternate type of instance for performing lookups.</typeparam>
-        <summary>Gets an instance of a type that can be used to perform operations on the current <see cref="T:System.Collections.Generic.HashSet`1"/> using a <typeparamref name="TAlternate"/> instead of a <typeparamref name="T"/>.</summary>
+        <summary>Gets an instance of a type that can be used to perform operations on the current <see cref="T:System.Collections.Generic.HashSet`1" /> using a <typeparamref name="TAlternate" /> instead of a <typeparamref name="T" />.</summary>
         <returns>The created lookup instance.</returns>
-        <remarks>The set must use a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2"/> with <typeparamref name="TAlternate"/> and <typeparamref name="T"/>. If it doesn't, an exception is thrown.</remarks>
+        <remarks>The set must use a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2" /> with <typeparamref name="TAlternate" /> and <typeparamref name="T" />. If it doesn't, an exception is thrown.</remarks>
+        <exception cref="T:System.InvalidOperationException">The set's comparer is not compatible with <typeparamref name="TAlternate" />.</exception>
       </Docs>
     </Member>
     <Member MemberName="GetEnumerator">
@@ -2625,9 +2626,10 @@ The following example demonstrates how to merge two disparate sets. This example
       <Docs>
         <typeparam name="TAlternate">The alternate type of instance for performing lookups.</typeparam>
         <param name="lookup">The created lookup instance when the method returns true, or a default instance that should not be used if the method returns false.</param>
-        <summary>Gets an instance of a type that can be used to perform operations on the current <see cref="T:System.Collections.Generic.HashSet`1"/> using a <typeparamref name="TAlternate"/> instead of a <typeparamref name="T"/>.</summary>
-        <returns><see langword="true" /> if a lookup could be created; otherwise, <see langword="false" />.</returns>
-        <remarks>The set must use a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2"/> with <typeparamref name="TAlternate"/> and <typeparamref name="T"/>. If it doesn't, the method returns <see langword="false" />.</remarks>
+        <summary>Gets an instance of a type that can be used to perform operations on the current <see cref="T:System.Collections.Generic.HashSet`1" /> using a <typeparamref name="TAlternate" /> instead of a <typeparamref name="T" />.</summary>
+        <returns>
+          <see langword="true" /> if a lookup could be created; otherwise, <see langword="false" />.</returns>
+        <remarks>The set must use a comparer that implements <see cref="T:System.Collections.Generic.IAlternateEqualityComparer`2" /> with <typeparamref name="TAlternate" /> and <typeparamref name="T" />. If it doesn't, the method returns <see langword="false" />.</remarks>
       </Docs>
     </Member>
     <Member MemberName="TryGetValue">

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

@@ -1232,6 +1232,7 @@
  ]]></format>
         </remarks>
         <altmember cref="P:System.Collections.ICollection.SyncRoot" />
+        <inheritdoc cref="T:System.Collections.Generic.ICollection`1" />
       </Docs>
     </Member>
     <Member MemberName="System.Collections.ICollection.SyncRoot">

xml/System.IO.Compression/BrotliCompressionOptions.xml

@@ -31,7 +31,7 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Initializes a <see cref="T:System.IO.Compression.BrotliCompressionOptions" /> instance with default values.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>

xml/System.IO.Compression/ZLibCompressionOptions.xml

@@ -31,7 +31,7 @@
       </AssemblyInfo>
       <Parameters />
       <Docs>
-        <summary>To be added.</summary>
+        <summary>Initializes a <see cref="T:System.IO.Compression.ZLibCompressionOptions" /> instance with default values.</summary>
         <remarks>To be added.</remarks>
       </Docs>
     </Member>