Apply suggestions from code review

Co-authored-by: Vladimír Vondruš <mosra@centrum.cz>

src/Magnum/Math/DualComplex.h

@@ -108,7 +108,7 @@ template<class T> class DualComplex: public Dual<Complex<T>> {
         }
 
         /**
-         * @brief Create dual complexity from rotation complex and translation vector
+         * @brief Create dual complex from rotation complex and translation vector
          * @m_since_latest
          *
          * @f[

src/Magnum/Platform/Sdl2Application.cpp

@@ -887,7 +887,7 @@ bool Sdl2Application::mainLoopIteration() {
         switch(event.type) {
             case SDL_WINDOWEVENT:
                 switch(event.window.event) {
-                    /* Not using SDL_WINDOWEVENT_RESIZED, because that does't
+                    /* Not using SDL_WINDOWEVENT_RESIZED, because that doesn't
                        get fired when the window is resized programmatically
                        (such as through setMaxWindowSize()) */
                     case SDL_WINDOWEVENT_SIZE_CHANGED: {

src/Magnum/Primitives/Test/GradientTest.cpp

@@ -60,7 +60,7 @@ GradientTest::GradientTest() {
 using namespace Magnum::Math::Literals;
 
 void GradientTest::gradient2D() {
-    /* The corners could have 0.2, 0.4, 0.6, 0.8 blends */
+    /* The corners should have 0.2, 0.4, 0.6, 0.8 blends */
     Trade::MeshData gradient = Primitives::gradient2D(
         {-1.0f, 2.0f}, {0.2f, 0.6f, 1.0f},
         {1.0f, -2.0f}, {0.4f, 1.0f, 0.0f});
@@ -115,7 +115,7 @@ void GradientTest::gradient2DVertical() {
 }
 
 void GradientTest::gradient3D() {
-    /* The corners could have 0.2, 0.4, 0.6, 0.8 blends */
+    /* The corners should have 0.2, 0.4, 0.6, 0.8 blends */
     Trade::MeshData gradient = Primitives::gradient3D(
         {-1.0f, 2.0f, -1.5f}, {0.2f, 0.6f, 1.0f},
         {1.0f, -2.0f, -1.5f}, {0.4f, 1.0f, 0.0f});