Fix spelling error

Author: coke

doc/Type/Hash.pod6

@@ -657,7 +657,7 @@ The adverbs C<:v> and C<:k> return the key or value or a list their of.
     say %h<a>:k;    # a
     say %h<a b>:k;  # (a b)
 
-You can also use the adverbs without knowning anything about the hash by using 
+You can also use the adverbs without knowing anything about the hash by using
 empty angle brackets in which case all the keys and values will be listed:
 
     my %h1 = a => 1;