doc: updated changelog and credits.

doc/changelog.dox

@@ -275,6 +275,9 @@ See also:
     @gl_extension{EXT,instanced_arrays}, @gl_extension{EXT,draw_instanced},
     @gl_extension{NV,instanced_arrays} and @gl_extension{NV,draw_instanced}
     extensions
+-   @ref GL::Context would crash on destruction if it was constructed with
+    @ref NoCreate but @ref GL::Context::create() was never called (see
+    [mosra/magnum#331](https://github.com/mosra/magnum/pull/331)
 -   Reading of float textures on ES3 contexts using
     @ref DebugTools::textureSubImage() returned a zero-sized image by accident
 -   Properly zero-initializing the UTF-8 buffer in

doc/credits.dox

@@ -131,7 +131,7 @@ Are the below lists missing your name or something's wrong?
 -   **Leon Moctezuma** ([\@leonidax](https://github.com/leonidax)) ---
     bugreports, API design direction
 -   **Max Schwarz** ([\@xqms](https://github.com/xqms)) --- `Any*` plugin
-    improvements
+    improvements, fixes in the @ref GL library
 -   **Miguel Martin** ([\@miguelmartin75](https://github.com/miguelmartin75))
     --- initial macOS port, various other improvements
 -   **Nathan Ollerenshaw** ([\@matjam](https://github.com/matjam)) --- Ubuntu