Ruby: Simplify flow summaries for hash literals

[hvitved]

The existing summaries could be simplified using the models-as-data token Argument[hash-splat], which refers to both keyword arguments wrapped in an implicit hash, as well as explicit hash splat arguments.

[hmac]

Nice. As an optional addition, I thought it might be nice to add these two variants to the existing hash-flow.rb tests. I added them locally to confirm that things were working as expected.

diff --git a/ruby/ql/test/library-tests/dataflow/hash-flow/hash_flow.rb b/ruby/ql/test/library-tests/dataflow/hash-flow/hash_flow.rb
index f9de83dd47..06c57336a4 100644
--- a/ruby/ql/test/library-tests/dataflow/hash-flow/hash_flow.rb
+++ b/ruby/ql/test/library-tests/dataflow/hash-flow/hash_flow.rb
@@ -68,6 +68,14 @@ def m3()
     hash4 = Hash[:a, taint(3.4), :b, 1]
     sink(hash4[:a]) # $ hasValueFlow=3.4
     sink(hash4[:b])
+
+    hash5 = Hash["a" => taint(3.4), "b" => 1]
+    sink(hash5["a"]) # $ hasValueFlow=3.4
+    sink(hash5["b"])
+
+    hash6 = Hash[{"a" => taint(3.4), "b" => 1}]
+    sink(hash6["a"]) # $ hasValueFlow=3.4
+    sink(hash6["b"])
 end
 
 m3()
@@ -746,4 +754,4 @@ def m45()
     sink(hash[:h])
 end
 
-m45()
\ No newline at end of file
+m45()

But it doesn't need to block this PR

[hvitved]

Thanks, I'll add the additional tests.