ImVector: fix Clang warning (implicit conversion changes signedness: 'const ptrdiff_t' (aka 'const long long') to 'unsigned long long')

imgui.h

@@ -1742,7 +1742,7 @@ struct ImVector
     inline void         pop_back()                          { IM_ASSERT(Size > 0); Size--; }
     inline void         push_front(const T& v)              { if (Size == 0) push_back(v); else insert(Data, v); }
     inline T*           erase(const T* it)                  { IM_ASSERT(it >= Data && it < Data + Size); const ptrdiff_t off = it - Data; memmove(Data + off, Data + off + 1, ((size_t)Size - (size_t)off - 1) * sizeof(T)); Size--; return Data + off; }
-    inline T*           erase(const T* it, const T* it_last){ IM_ASSERT(it >= Data && it < Data + Size && it_last > it && it_last <= Data + Size); const ptrdiff_t count = it_last - it; const ptrdiff_t off = it - Data; memmove(Data + off, Data + off + count, ((size_t)Size - (size_t)off - count) * sizeof(T)); Size -= (int)count; return Data + off; }
+    inline T*           erase(const T* it, const T* it_last){ IM_ASSERT(it >= Data && it < Data + Size && it_last > it && it_last <= Data + Size); const ptrdiff_t count = it_last - it; const ptrdiff_t off = it - Data; memmove(Data + off, Data + off + count, ((size_t)Size - (size_t)off - (size_t)count) * sizeof(T)); Size -= (int)count; return Data + off; }
     inline T*           erase_unsorted(const T* it)         { IM_ASSERT(it >= Data && it < Data + Size);  const ptrdiff_t off = it - Data; if (it < Data + Size - 1) memcpy(Data + off, Data + Size - 1, sizeof(T)); Size--; return Data + off; }
     inline T*           insert(const T* it, const T& v)     { IM_ASSERT(it >= Data && it <= Data + Size); const ptrdiff_t off = it - Data; if (Size == Capacity) reserve(_grow_capacity(Size + 1)); if (off < (int)Size) memmove(Data + off + 1, Data + off, ((size_t)Size - (size_t)off) * sizeof(T)); memcpy(&Data[off], &v, sizeof(v)); Size++; return Data + off; }
     inline bool         contains(const T& v) const          { const T* data = Data;  const T* data_end = Data + Size; while (data < data_end) if (*data++ == v) return true; return false; }