Add test for augmenting ret and assign in block

Author: JSAbrahams

tests/resource/valid/definition/assign_with_nested_if.mamba

@@ -1,6 +1,7 @@
 def x := 20
 def a: Int := if x > 10 then
     if x > 30 then
+        print("string")
         x + 1
     else
         x - 1

tests/resource/valid/definition/assign_with_nested_if_check.py

@@ -1,6 +1,7 @@
 x: int = 20
 if x > 10:
     if x > 30:
+        print("string")
         a = x + 1
     else:
         a = x - 1

tests/resource/valid/definition/function_with_nested_if.mamba

@@ -1,6 +1,7 @@
 def f(x: Int) -> Int =>
     if x > 10 then
         if x > 30 then
+            print("string")
             x + 1
         else
             x - 1

tests/resource/valid/definition/function_with_nested_if_check.py

@@ -1,6 +1,7 @@
 def f(x: int) -> int:
     if x > 10:
         if x > 30:
+            print("string")
             return x + 1
         else:
             return x - 1