Add missing docs for Task API (dotnet#10405)

* Add missing docs for Task API

* Apply suggestions from code review

Author: ericstj

xml/System.Threading.Tasks.Sources/ManualResetValueTaskSourceCore`1.xml

@@ -57,7 +57,7 @@
     </Attribute>
   </Attributes>
   <Docs>
-    <typeparam name="TResult" />
+    <typeparam name="TResult">Specifies the type of results of the operation represented by this instance.</typeparam>
     <summary>Provides the core logic for implementing a manual-reset <see cref="T:System.Threading.Tasks.Sources.IValueTaskSource" /> or <see cref="T:System.Threading.Tasks.Sources.IValueTaskSource`1" />.</summary>
     <remarks>To be added.</remarks>
   </Docs>
@@ -308,7 +308,7 @@
         <Parameter Name="error" Type="System.Exception" />
       </Parameters>
       <Docs>
-        <param name="error" />
+        <param name="error">The exception.</param>
         <summary>Complets with an error.</summary>
         <remarks>To be added.</remarks>
       </Docs>

xml/System.Threading.Tasks/Task.xml

@@ -6720,7 +6720,7 @@ An exception was thrown during
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TResult">To be added.</typeparam>
+        <typeparam name="TResult">The type of the result returned by the tasks.</typeparam>
         <param name="tasks">The tasks to wait on for completion.</param>
         <summary>Creates a task that will complete when all of the supplied tasks have completed.</summary>
         <returns>A task that represents the completion of all of the supplied tasks.</returns>
@@ -7178,7 +7178,7 @@ The returned task will complete when any of the supplied tasks has completed.  T
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TResult">To be added.</typeparam>
+        <typeparam name="TResult">The type of the result returned by the tasks.</typeparam>
         <param name="tasks">The tasks to wait on for completion.</param>
         <summary>Creates a task that will complete when any of the supplied tasks have completed.</summary>
         <returns>A task that represents the completion of one of the supplied tasks.  The return Task's Result is the task that completed.</returns>
@@ -7352,7 +7352,7 @@ The returned task will complete when any of the supplied tasks has completed.  T
         <Parameter Name="tasks" Type="System.Collections.Generic.IEnumerable&lt;System.Threading.Tasks.Task&gt;" Index="0" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <param name="tasks">To be added.</param>
+        <param name="tasks">The tasks to iterate through as they complete.</param>
         <summary>To be added.</summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
@@ -7394,7 +7394,7 @@ The returned task will complete when any of the supplied tasks has completed.  T
         </Parameter>
       </Parameters>
       <Docs>
-        <param name="tasks">To be added.</param>
+        <param name="tasks">The tasks to iterate through as they complete.</param>
         <summary>To be added.</summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
@@ -7484,8 +7484,8 @@ The returned task will complete when any of the supplied tasks has completed.  T
         <Parameter Name="tasks" Type="System.Collections.Generic.IEnumerable&lt;System.Threading.Tasks.Task&lt;TResult&gt;&gt;" Index="0" FrameworkAlternate="net-9.0" />
       </Parameters>
       <Docs>
-        <typeparam name="TResult">To be added.</typeparam>
-        <param name="tasks">To be added.</param>
+        <typeparam name="TResult">The type of the result returned by the tasks.</typeparam>
+        <param name="tasks">The tasks to iterate through as they complete.</param>
         <summary>To be added.</summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
@@ -7537,8 +7537,8 @@ The returned task will complete when any of the supplied tasks has completed.  T
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TResult">To be added.</typeparam>
-        <param name="tasks">To be added.</param>
+        <typeparam name="TResult">The type of the result returned by the tasks.</typeparam>
+        <param name="tasks">The tasks to iterate through as they complete.</param>
         <summary>To be added.</summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>
@@ -7590,8 +7590,8 @@ The returned task will complete when any of the supplied tasks has completed.  T
         </Parameter>
       </Parameters>
       <Docs>
-        <typeparam name="TResult">To be added.</typeparam>
-        <param name="tasks">To be added.</param>
+        <typeparam name="TResult">The type of the result returned by the tasks.</typeparam>
+        <param name="tasks">The tasks to iterate through as they complete.</param>
         <summary>To be added.</summary>
         <returns>To be added.</returns>
         <remarks>To be added.</remarks>