Fix typo (#4239)

Author: Vlad Iovanov

xml/Microsoft.Extensions.Caching.Distributed/IDistributedCache.xml

@@ -133,7 +133,7 @@
         <Parameter Name="key" Type="System.String" />
       </Parameters>
       <Docs>
-        <param name="key">A string identifying the requested calue.</param>
+        <param name="key">A string identifying the requested value.</param>
         <summary>Refreshes a value in the cache based on its key, resetting its sliding expiration timeout (if any).</summary>
         <remarks>To be added.</remarks>
       </Docs>