tests: Trim .nim files trailing whitespace

via OSX: find . -name '*.nim' -exec sed -i '' -E 's/[[:space:]]+$//' {} +

tests/range/tmatrix3.nim

@@ -10,11 +10,11 @@ discard """
 include compilehelpers
 
 type
-  Matrix*[M, N, T] = object 
+  Matrix*[M, N, T] = object
     aij*: array[M, array[N, T]]
-  
+
   Matrix2*[T] = Matrix[range[0..1], range[0..1], T]
-  
+
   Matrix3*[T] = Matrix[range[0..2], range[0..2], T]
 
 proc mn(x: Matrix): Matrix.T = x.aij[0][0]
@@ -23,7 +23,7 @@ proc m2(x: Matrix2): Matrix2.T = x.aij[0][0]
 
 proc m3(x: Matrix3): auto = x.aij[0][0]
 
-var 
+var
   matn: Matrix[range[0..3], range[0..2], int]
   mat2: Matrix2[int]
   mat3: Matrix3[float]