FDS Source: fix indent

Author: drjfloyd

Source/func.f90

@@ -9296,7 +9296,7 @@ REAL(EB) FUNCTION CIRCLE_CELL_INTERSECTION_AREA(X0,Y0,RAD,X1,X2,Y1,Y2)
 
 SELECT CASE(FC)
    ! No corners either full area or circle minus one or more chords
-CASE (0)
+   CASE (0)
       ! First four cases are more than half the cirlce outside the rectangle.
       ! Can only have one edge where this is the case without having a corner inside. This edge makes a chord.
       ! Intersection area is the circle area minus the area of the chord.