Cleanup: correct comments in scanfill.c, don't use bool for a flag

Logically PolyFill::f is a flag so use uchar instead of bool.

source/blender/blenlib/intern/scanfill.c

@@ -39,7 +39,7 @@ typedef struct PolyFill {
   uint edges, verts;
   float min_xy[2], max_xy[2];
   ushort nr;
-  bool f;
+  uchar f;
 } PolyFill;
 
 typedef struct ScanFillVertLink {
@@ -52,19 +52,19 @@ typedef struct ScanFillVertLink {
 #define SF_EPSILON 0.00003f
 #define SF_EPSILON_SQ (SF_EPSILON * SF_EPSILON)
 
-/** #ScanFillVert.status */
+/** #ScanFillVert::f (status) */
 #define SF_VERT_NEW 0       /* all new verts have this flag set */
 #define SF_VERT_AVAILABLE 1 /* available - in an edge */
 #define SF_VERT_ZERO_LEN 2
 
-/** #ScanFillEdge.status */
+/** #ScanFillEdge::f (status) */
 /* Optionally set ScanFillEdge f to this to mark original boundary edges.
  * Only needed if there are internal diagonal edges passed to BLI_scanfill_calc. */
 #define SF_EDGE_NEW 0 /* all new edges have this flag set */
 // #define SF_EDGE_BOUNDARY 1  /* UNUSED */
 #define SF_EDGE_INTERNAL 2 /* edge is created while scan-filling */
 
-/** #PolyFill.status */
+/** #PolyFill::f (status) */
 #define SF_POLY_NEW 0   /* all polys initialized to this */
 #define SF_POLY_VALID 1 /* has at least 3 verts */