Change isSlice to packsOf where needed

Author: jmh530

source/mir/ndslice/algorithm.d

@@ -1470,7 +1470,7 @@ template count(alias fun)
         else
         {
             static if (isSlice!(Slices[0]))
-                enum flat = Slices.length == 1 && kindOf!(Slices[0]) == Contiguous && isSlice!(Slices[0]) != [1];
+                enum flat = Slices.length == 1 && kindOf!(Slices[0]) == Contiguous && packsOf!(Slices[0]) != [1];
             else
                 enum flat = false;
             static if (flat)

source/mir/ndslice/slice.d

@@ -2118,7 +2118,7 @@ struct Slice(SliceKind kind, size_t[] packs, Iterator)
         {
             import mir.ndslice.topology : unpack;
             auto sl = this[slices].unpack;
-            static assert(isSlice!(typeof(sl))[0] == concatenation.N);
+            static assert(packsOf!(typeof(sl))[0] == concatenation.N);
             sl.opIndexOpAssignImplConcatenation!""(concatenation);
         }
 
@@ -2437,7 +2437,7 @@ struct Slice(SliceKind kind, size_t[] packs, Iterator)
         {
             import mir.ndslice.topology : unpack;
             auto sl = this[slices].unpack;
-            static assert(isSlice!(typeof(sl))[0] == concatenation.N);
+            static assert(packsOf!(typeof(sl))[0] == concatenation.N);
             sl.opIndexOpAssignImplConcatenation!op(concatenation);
         }
 

source/mir/ndslice/topology.d

@@ -2475,10 +2475,10 @@ auto zip
     (bool sameStrides = false, Slices...)(Slices slices)
     if (Slices.length > 1 && allSatisfy!(isSlice, Slices))
 {
-    enum packs = isSlice!(Slices[0]);
+    enum packs = packsOf!(Slices[0]);
     foreach(i, S; Slices[1 .. $])
     {
-        static assert(isSlice!S == packs, "zip: all Slices must have the same shape packs");
+        static assert(packsOf!S == packs, "zip: all Slices must have the same shape packs");
         assert(slices[i + 1]._lengths == slices[0]._lengths, "zip: all slices must have the same lengths");
         static if (sameStrides)
             assert(slices[i + 1].unpack.strides == slices[0].unpack.strides, "zip: all slices must have the same strides when unpacked");