Add GDScript .editorconfig rules

- Uniformize `.gd` unit test files indentation to tabs (where needed)

modules/gdscript/tests/scripts/analyzer/features/lookup_class.gd

@@ -1,50 +1,50 @@
 # Inner-outer class lookup
 class A:
-    const Q: = "right one"
+	const Q: = "right one"
 
 class X:
-    const Q: = "wrong one"
+	const Q: = "wrong one"
 
 class Y extends X:
-    class B extends A:
-        static func check() -> void:
-            print(Q)
+	class B extends A:
+		static func check() -> void:
+			print(Q)
 
 # External class lookup
 const External: = preload("lookup_class_external.notest.gd")
 
 class Internal extends External.A:
-    static func check() -> void:
-        print(TARGET)
+	static func check() -> void:
+		print(TARGET)
 
-    class E extends External.E:
-        static func check() -> void:
-            print(TARGET)
-            print(WAITING)
+	class E extends External.E:
+		static func check() -> void:
+			print(TARGET)
+			print(WAITING)
 
 # Variable lookup
 class C:
-    var Q := 'right one'
+	var Q := 'right one'
 
 class D:
-    const Q := 'wrong one'
+	const Q := 'wrong one'
 
 class E extends D:
-    class F extends C:
-        func check() -> void:
-            print(Q)
+	class F extends C:
+		func check() -> void:
+			print(Q)
 
 # Test
 func test() -> void:
-    # Inner-outer class lookup
-    Y.B.check()
-    print("---")
+	# Inner-outer class lookup
+	Y.B.check()
+	print("---")
 
-    # External class lookup
-    Internal.check()
-    Internal.E.check()
-    print("---")
+	# External class lookup
+	Internal.check()
+	Internal.E.check()
+	print("---")
 
-    # Variable lookup
-    var f: = E.F.new()
-    f.check()
+	# Variable lookup
+	var f: = E.F.new()
+	f.check()