Fix issue #47 - Add missing parentheses so dub build --build=docs works.

source/raylib/rlgl.d

@@ -75,7 +75,7 @@ import raylib;
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_VIEW        "matView"           // view matrix
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_PROJECTION  "matProjection"     // projection matrix
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_MODEL       "matModel"          // model matrix
-*       #define RL_DEFAULT_SHADER_UNIFORM_NAME_NORMAL      "matNormal"         // normal matrix (transpose(inverse(matModelView))
+*       #define RL_DEFAULT_SHADER_UNIFORM_NAME_NORMAL      "matNormal"         // normal matrix (transpose(inverse(matModelView)))
 *       #define RL_DEFAULT_SHADER_UNIFORM_NAME_COLOR       "colDiffuse"        // color diffuse (base tint color, multiplied by texture color)
 *       #define RL_DEFAULT_SHADER_SAMPLER2D_NAME_TEXTURE0  "texture0"          // texture0 (texture slot active 0)
 *       #define RL_DEFAULT_SHADER_SAMPLER2D_NAME_TEXTURE1  "texture1"          // texture1 (texture slot active 1)