[xkb] swap afnor spacebar for bépo's

config/xkb/symbols/custom

@@ -23,4 +23,7 @@ xkb_symbols "fr_afnor" {
 
     key <AB01>	{[           w,              W,            less,    lessthanequal ]}; // w W < ≤
     key <AB02>	{[           x,              X,         greater, greaterthanequal ]}; // x X > ≥
+
+    // Space bar borrowed from bépo
+    key <SPCE>	{[       space,   nobreakspace,      underscore,            U202F ]}; // ␣ (espace insécable) _ (espace insécable fin)
 };