Remove line from every signature meta (#1592)

Fixes: #1591

Author: Eiji7

lib/ex_doc/language/elixir.ex

@@ -364,6 +364,7 @@ defmodule ExDoc.Language.Elixir do
       {{:|, _, _}, position} -> to_var({}, position)
       {left, position} -> to_var(left, position)
     end)
+    |> Macro.prewalk(fn node -> Macro.update_meta(node, &Keyword.delete(&1, :line)) end)
   end
 
   defp to_var({:%, meta, [name, _]}, _), do: {:%, meta, [name, {:%{}, meta, []}]}

test/ex_doc/retriever_test.exs

@@ -190,4 +190,22 @@ defmodule ExDoc.RetrieverTest do
     assert function_B_0.id == "function_B/0"
     assert function_b_0.id == "function_b/0"
   end
+
+  test "no whitespace in signature", c do
+    elixirc(c, ~S"""
+    defmodule NoWhitespaceInSignature do
+      @callback callback_name(
+        arg1 :: integer(),
+        1,
+        %Date{},
+        term,
+        String.t()
+      ) :: :ok
+    end
+    """)
+
+    [module_node] = Retriever.docs_from_modules([NoWhitespaceInSignature], %ExDoc.Config{})
+    %{docs: [%{signature: signature}]} = module_node
+    assert signature == "callback_name(arg1, integer, %Date{}, term, t)"
+  end
 end