Fixed typo in definition (#8065)

Author: ChrisVo

xml/System/Span`1.xml

@@ -50,7 +50,7 @@
   </Attributes>
   <Docs>
     <typeparam name="T">The type of items in the <see cref="T:System.Span`1" />.</typeparam>
-    <summary>Provides a type- and memory-safe representation of a contiguous region of arbitrary memory.</summary>
+    <summary>Provides a type-safe and memory-safe representation of a contiguous region of arbitrary memory.</summary>
     <remarks>
       <format type="text/markdown"><![CDATA[