Math: remove swizzle() that was deprecated since 2019.10.

doc/changelog.dox

@@ -1132,6 +1132,8 @@ See also:
         @cpp Trade::AbstractMaterialData::AbstractMaterialData(MaterialType, Flags, MaterialAlphaMode, Float, const void*) @ce
         and @cpp Trade::PhongMaterialData::PhongMaterialData(Flags, MaterialAlphaMode, Float, Float, const void*) @ce
         constructors or directly the new @ref Trade::MaterialData class
+-   Removed APIs deprecated in 2019.10, in particular:
+    -   @cpp Math::swizzle() @ce, use @ref Math::gather() instead
 -   All includes of @ref Corrade/Containers/PointerStl.h and
     @ref Corrade/Containers/ArrayViewStl.h that were added in 2019.01 for
     preserving backwards compatibility after the move from @ref std::unique_ptr

src/Magnum/Math/Swizzle.h

@@ -154,15 +154,6 @@ template<char ...components, class T> constexpr T scatter(const T& vector, const
     return Implementation::scatterRecursive<T, sizeof...(components), components...>(vector, values, 0);
 }
 
-#ifdef MAGNUM_BUILD_DEPRECATED
-/** @brief @copybrief gather()
- * @m_deprecated_since{2019,10} Use @ref gather() instead.
- */
-template<char ...components, class T> CORRADE_DEPRECATED("use gather() instead") constexpr typename Implementation::TypeForSize<sizeof...(components), T>::Type swizzle(const T& vector) {
-    return gather<components...>(vector);
-}
-#endif
-
 }}
 
 #endif