Undocument eye textures as an enum

i was wrong: `_Draw` function might not follow the eyes texture order
it is its own thing, like `enum EnMdBlinking` or nothing at all, yeah

src/overlays/actors/ovl_En_Md/z_en_md.c

@@ -545,9 +545,9 @@ u8 EnMd_ShouldSpawn(EnMd* this, PlayState* play) {
 void EnMd_UpdateEyes(EnMd* this) {
     if (DECR(this->blinkTimer) == 0) {
         this->eyeTexIndex++;
-        if (this->eyeTexIndex > ENMD_EYE_CLOSED) {
+        if (this->eyeTexIndex > 0) {
             this->blinkTimer = Rand_S16Offset(30, 30);
-            this->eyeTexIndex = ENMD_EYE_OPEN;
+            this->eyeTexIndex = 2;
         }
     }
 }

src/overlays/actors/ovl_En_Md/z_en_md.h

@@ -27,15 +27,6 @@ typedef enum EnMdLimb {
     ENMD_LIMB_MAX
 } EnMdLimb;
 
-typedef enum EnMdEye {
-    ENMD_EYE_OPEN,
-    ENMD_EYE_HALF,
-    ENMD_EYE_CLOSED,
-    ENMD_EYE_ANGRY,
-    ENMD_EYE_LOOKING_UP,
-    ENMD_EYE_MAX
-} EnMdEye;
-
 typedef void (*EnMdActionFunc)(struct EnMd*, PlayState*);
 
 typedef struct EnMd {