GL: compile forgotten code snippets.

Also wrap long lines to avoid ugly scrollbars.

doc/snippets/MagnumGL-framebuffer.cpp

@@ -40,7 +40,8 @@ void viewportEvent(ViewportEvent& event) override {
 
 /* [DefaultFramebuffer-usage-clear] */
 void drawEvent() override {
-    GL::defaultFramebuffer.clear(GL::FramebufferClear::Color|GL::FramebufferClear::Depth);
+    GL::defaultFramebuffer.clear(GL::FramebufferClear::Color|
+                                 GL::FramebufferClear::Depth);
 
     // ...
 }
@@ -54,7 +55,9 @@ GL::Framebuffer framebuffer;
 /* [Framebuffer-usage-draw] */
 void drawEvent() override {
     GL::defaultFramebuffer.clear(GL::FramebufferClear::Color);
-    framebuffer.clear(GL::FramebufferClear::Color|GL::FramebufferClear::Depth|GL::FramebufferClear::Stencil);
+    framebuffer.clear(GL::FramebufferClear::Color|
+                      GL::FramebufferClear::Depth|
+                      GL::FramebufferClear::Stencil);
 
     framebuffer.bind();
     // ...

doc/snippets/MagnumGL.cpp

@@ -894,7 +894,8 @@ GL::Renderbuffer depthStencil;
 
 framebuffer.attachTexture(GL::Framebuffer::ColorAttachment{0}, color, 0);
 framebuffer.attachTexture(GL::Framebuffer::ColorAttachment{1}, normal, 0);
-framebuffer.attachRenderbuffer(GL::Framebuffer::BufferAttachment::DepthStencil, depthStencil);
+framebuffer.attachRenderbuffer(
+    GL::Framebuffer::BufferAttachment::DepthStencil, depthStencil);
 /* [Framebuffer-usage-attach] */
 }
 #endif
@@ -908,9 +909,16 @@ struct MyShader {
 };
 GL::Framebuffer framebuffer{{}};
 /* [Framebuffer-usage-map] */
-framebuffer.mapForDraw({{MyShader::ColorOutput, GL::Framebuffer::ColorAttachment(0)},
+framebuffer.mapForDraw({
-                        {MyShader::NormalOutput, GL::Framebuffer::ColorAttachment(1)}});
+    {MyShader::ColorOutput, GL::Framebuffer::ColorAttachment(0)},
+    {MyShader::NormalOutput, GL::Framebuffer::ColorAttachment(1)}});
 /* [Framebuffer-usage-map] */
+
+/* [Framebuffer-mapForDraw] */
+framebuffer.mapForDraw({
+    {MyShader::ColorOutput, GL::Framebuffer::ColorAttachment(0)},
+    {MyShader::NormalOutput, GL::Framebuffer::DrawAttachment::None}});
+/* [Framebuffer-mapForDraw] */
 }
 
 {
@@ -1235,6 +1243,15 @@ GL::CompressedBufferImage2D image = texture.compressedSubImage(range, {},
 }
 #endif
 
+{
+GL::Renderer::Feature feature = GL::Renderer::Feature::Blending;
+bool enabled{};
+/* [Renderer-setFeature] */
+enabled ? GL::Renderer::enable(feature) : GL::Renderer::disable(feature)
+/* [Renderer-setFeature] */
+;
+}
+
 #if !(defined(MAGNUM_TARGET_GLES2) && defined(MAGNUM_TARGET_WEBGL))
 {
 /* [SampleQuery-usage] */

src/Magnum/GL/Framebuffer.h

@@ -490,10 +490,7 @@ class MAGNUM_GL_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractO
          * used, you can achieve the same by passing @ref Framebuffer::DrawAttachment::None
          * as color attachment ID. Example usage:
          *
-         * @code{.cpp}
+         * @snippet MagnumGL.cpp Framebuffer-mapForDraw
-         * framebuffer.mapForDraw({{MyShader::ColorOutput, Framebuffer::ColorAttachment(0)},
-         *                         {MyShader::NormalOutput, Framebuffer::DrawAttachment::None}});
-         * @endcode
          *
          * If neither @gl_extension{ARB,direct_state_access} (part of OpenGL 4.5)
          * nor @gl_extension{EXT,direct_state_access} desktop extension is

src/Magnum/GL/Renderer.h

@@ -331,9 +331,7 @@ class MAGNUM_GL_EXPORT Renderer {
          *
          * Convenience equivalent to the following:
          *
-         * @code{.cpp}
+         * @snippet MagnumGL.cpp Renderer-setFeature
-         * enabled ? Renderer::enable(feature) : Renderer::disable(feature)
-         * @endcode
          *
          * Prefer to use @ref enable() and @ref disable() directly to avoid
          * unnecessary branching.