GL: minor code reordering, doc++.

Getter and setter *should* be next to each other. I was horrified for 9
seconds that there's no setViewport().

src/Magnum/GL/AbstractFramebuffer.h

@@ -263,6 +263,19 @@ class MAGNUM_GL_EXPORT AbstractFramebuffer {
         /** @brief Viewport rectangle */
         Range2Di viewport() const { return _viewport; }
 
+        /**
+         * @brief Set viewport
+         * @return Reference to self (for method chaining)
+         *
+         * Saves the viewport to be used at later time in @ref bind(). If the
+         * framebuffer is currently bound, updates the viewport to given
+         * rectangle. Initial value in @ref DefaultFramebuffer is set to cover
+         * whole window, in @ref Framebuffer the initial value is specified in
+         * constructor.
+         * @see @ref maxViewportSize(), @fn_gl_keyword{Viewport}
+         */
+        AbstractFramebuffer& setViewport(const Range2Di& rectangle);
+
         /**
          * @brief Implementation-specific color read format
          *
@@ -295,19 +308,6 @@ class MAGNUM_GL_EXPORT AbstractFramebuffer {
          */
         PixelType implementationColorReadType();
 
-        /**
-         * @brief Set viewport
-         * @return Reference to self (for method chaining)
-         *
-         * Saves the viewport to be used at later time in @ref bind(). If the
-         * framebuffer is currently bound, updates the viewport to given
-         * rectangle. Initial value in @ref DefaultFramebuffer is set to cover
-         * whole window, in @ref Framebuffer the initial value is specified in
-         * constructor.
-         * @see @ref maxViewportSize(), @fn_gl_keyword{Viewport}
-         */
-        AbstractFramebuffer& setViewport(const Range2Di& rectangle);
-
         /**
          * @brief Clear specified buffers in the framebuffer
          * @param mask              Which buffers to clear

src/Magnum/GL/Framebuffer.h

@@ -502,7 +502,7 @@ class MAGNUM_GL_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractO
         Framebuffer& mapForDraw(std::initializer_list<std::pair<UnsignedInt, DrawAttachment>> attachments);
 
         /**
-         * @brief Map shader output to attachment
+         * @brief Map shader output to an attachment
          * @param attachment        Draw attachment
          * @return Reference to self (for method chaining)
          *