Updated package description with new types

Author: Sergio0694

Microsoft.Toolkit.HighPerformance/Microsoft.Toolkit.HighPerformance.csproj

@@ -8,12 +8,13 @@
     <Title>Windows Community Toolkit High Performance .NET Standard</Title>
     <Description>
       This package includes high performance .NET Standard helpers such as:
+      - Memory2D&lt;T&gt; and Span2D&lt;T&gt;: two types providing fast and allocation-free abstraction over 2D memory areas.
       - ArrayPoolBufferWriter&lt;T&gt;: an IBufferWriter&lt;T&gt; implementation using pooled arrays, which also supports IMemoryOwner&lt;T&gt;.
       - MemoryBufferWriter&lt;T&gt;: an IBufferWriter&lt;T&gt;: implementation that can wrap external Memory&lt;T&gt;: instances.
       - MemoryOwner&lt;T&gt;: an IMemoryOwner&lt;T&gt; implementation with an embedded length and a fast Span&lt;T&gt; accessor.
       - SpanOwner&lt;T&gt;: a stack-only type with the ability to rent a buffer of a specified length and getting a Span&lt;T&gt; from it.
       - StringPool: a configurable pool for string instances that be used to minimize allocations when creating multiple strings from char buffers.
-      - String, array, Span&lt;T&gt;, Memory&lt;T&gt; extensions and more, all focused on high performance.
+      - String, array, Memory&lt;T&gt;, Span&lt;T&gt; extensions and more, all focused on high performance.
       - HashCode&lt;T&gt;: a SIMD-enabled extension of HashCode to quickly process sequences of values.
       - BitHelper: a class with helper methods to perform bit operations on numeric types.
       - ParallelHelper: helpers to work with parallel code in a highly optimized manner.