Text: fix error in fontconverter utility documentation.

src/Text/fontconverter.cpp

@@ -55,7 +55,7 @@ FontConverter::FontConverter(const Arguments& arguments): Platform::WindowlessAp
         .addOption("characters", "abcdefghijklmnopqrstuvwxyz"
                                  "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                                  "0123456789?!:,. ").setHelp("characters", "characters to include in the output")
-        .addOption("font-size", "128").setHelpKey("font-size", "\"X Y\"").setHelp("font-size", "TTF font size")
+        .addOption("font-size", "128").setHelpKey("font-size", "N").setHelp("font-size", "TTF font size")
         .addOption("atlas-size", "2048 2048").setHelpKey("atlas-size", "\"X Y\"").setHelp("atlas-size", "glyph atlas size")
         .addOption("output-size", "256 256").setHelpKey("output-size", "\"X Y\"").setHelp("output-size", "output atlas size. If set to zero size, distance field computation will not be used.")
         .addOption("radius", "24").setHelpKey("radius", "N").setHelp("radius", "distance field computation radius")