Show the file name in the location if the file is included (#383)

test/contracts/namespace_clash_included.aes

@@ -0,0 +1,9 @@
+@compiler >= 6
+
+include "BLS12_381.aes"
+
+namespace BLS12_381 =
+    type fp = int
+
+main contract Bug =
+    type number = int

test/contracts/namespace_clash_same_file.aes

@@ -0,0 +1,8 @@
+namespace Nmsp =
+    type x = int
+
+namespace Nmsp =
+    type y = string
+
+main contract Bug =
+    type number = int