Update xml/System.Collections.Frozen/FrozenDictionary`2.xml

Co-authored-by: Carlos Sánchez López <[email protected]>

Author: eiriktsarpalis

xml/System.Collections.Frozen/FrozenDictionary`2.xml

@@ -1222,7 +1222,7 @@
       </Parameters>
       <Docs>
         <typeparam name="TAlternateKey">The alternate type of a key for performing lookups.</typeparam>
-        <param name="lookup">The created lookup instance when the method returns true, or a default instance that should not be used if the method returns false.</param>
+        <param name="lookup">The created lookup instance when the method returns <see langword="true" />, or a default instance that should not be used if the method returns <see langword="false" />.</param>
         <summary>
           Gets an instance of a type that may be used to perform operations on a <see cref="T:System.Collections.Frozen.FrozenDictionary`2"/>
           using a <typeparamref name="TAlternateKey"/> as a key instead of a <typeparamref name="TKey"/>.