Fix wrong documentation

It doesn't return `nil` but raises an exception, as explained a few lines after

1 files changed, 0 insertions, 1 deletions

diff --git a/hash.c b/hash.c
index 1498f30f5a..a36310209b 100644
--- a/hash.c
+++ b/hash.c
@@ -2120,7 +2120,6 @@ rb_hash_lookup(VALUE hash, VALUE key)
  *  If +key+ is not found and no block was given,
  *  returns +default_value+:
  *    {}.fetch(:nosuch, :default) # => :default
- *    {}.fetch(:nosuch) # => nil
  *
  *  If +key+ is not found and a block was given,
  *  yields +key+ to the block and returns the block's return value: