fixup: typo

Author: illwieckz

src/engine/renderer/glsl_source/cameraEffects_fp.glsl

@@ -35,7 +35,7 @@ IN(smooth) vec2		var_TexCoords;
 
 DECLARE_OUTPUT(vec4)
 
-// Tone mapping is not available when high-precision float framebuffer isn't enable or supported.
+// Tone mapping is not available when high-precision float framebuffer isn't enabled or supported.
 #if defined(r_highPrecisionRendering) && defined(HAVE_ARB_texture_float)
 /* x: contrast
 y: highlightsCompressionSpeed