Allow ConcurrentDictionary concurrencyLevel == -1 in .NET 8+ (dotnet#8842)

Author: jeffhandley

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

@@ -351,7 +351,7 @@
         <Parameter Name="capacity" Type="System.Int32" />
       </Parameters>
       <Docs>
-        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently.</param>
+        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently, or in .NET 8+ only, -1 to indicate the default concurrency level.</param>
         <param name="capacity">The initial number of elements that the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> can contain.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> class that is empty, has the specified concurrency level and capacity, and uses the default comparer for the key type.</summary>
         <remarks>To be added.</remarks>
@@ -400,7 +400,7 @@
         <Parameter Name="comparer" Type="System.Collections.Generic.IEqualityComparer&lt;TKey&gt;" />
       </Parameters>
       <Docs>
-        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently.</param>
+        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently, or in .NET 8+ only, -1 to indicate the default concurrency level.</param>
         <param name="collection">The <see cref="T:System.Collections.Generic.IEnumerable`1" /> whose elements are copied to the new <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" />.</param>
         <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> implementation to use when comparing keys.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> class that contains elements copied from the specified <see cref="T:System.Collections.IEnumerable" />, and uses the specified <see cref="T:System.Collections.Generic.IEqualityComparer`1" />.</summary>
@@ -450,7 +450,7 @@
         <Parameter Name="comparer" Type="System.Collections.Generic.IEqualityComparer&lt;TKey&gt;" />
       </Parameters>
       <Docs>
-        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently.</param>
+        <param name="concurrencyLevel">The estimated number of threads that will update the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> concurrently, or in .NET 8+ only, -1 to indicate the default concurrency level.</param>
         <param name="capacity">The initial number of elements that the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> can contain.</param>
         <param name="comparer">The <see cref="T:System.Collections.Generic.IEqualityComparer`1" /> implementation to use when comparing keys.</param>
         <summary>Initializes a new instance of the <see cref="T:System.Collections.Concurrent.ConcurrentDictionary`2" /> class that is empty, has the specified concurrency level, has the specified initial capacity, and uses the specified <see cref="T:System.Collections.Generic.IEqualityComparer`1" />.</summary>