Revert part of own r51193 (now I know where Courant comes from...), and add another exception to UI messages spellchecker! Thanks to Lockal for pointing this.

release/scripts/modules/bl_i18n_utils/spell_check_utils.py

@@ -376,6 +376,7 @@ dict_uimsgs = {
     "catmull",
     "catrom",
     "chebychev",
+    "courant",
     "kutta",
     "lennard",
     "minkowski",

source/blender/makesrna/intern/rna_particle.c

@@ -2135,7 +2135,7 @@ static void rna_def_particle_settings(BlenderRNA *brna)
 	RNA_def_property_float_default(prop, 0.2);
 	RNA_def_property_ui_text(prop, "Adaptive Subframe Threshold",
 	                         "The relative distance a particle can move before requiring more subframes "
-	                         "(target current number); 0.1-0.3 is the recommended range");
+	                         "(target Courant number); 0.1-0.3 is the recommended range");
 	RNA_def_property_update(prop, 0, "rna_Particle_reset");
 
 	prop = RNA_def_property(srna, "jitter_factor", PROP_FLOAT, PROP_NONE);