Fix badly copypasted documentation.

Doxygen complains that it cannot find the \ce in there, heh. I copied
this from a `git stash show` view in Konsole, and SOMEHOW that thing no
longer copies the original text but inserts random newlines where the
terminal itself wrapped the text. Sometimes it works, sometimes not.
Code rot, code rot everywhere.

src/Magnum/PixelStorage.h

@@ -211,8 +211,7 @@ class MAGNUM_EXPORT CompressedPixelStorage: public PixelStorage {
         /**
          * @brief Data properties for given parameters
          *
-         * Returns byte offset in each direction and @cpp {rowLength, rowCount,
- layerCount} @ce
+         * Returns byte offset in each direction and @cpp {rowLength, rowCount, layerCount} @ce
          * *in blocks* for image of given @p size with current pixel storage
          * parameters. Sum of the byte offset vector gives the byte offset of
          * first block in the data array.