Add a comment to docs about using H-mode constraint most of the time

Author: timothy-nunn

documentation/physics-models/plasma_h_mode.md

@@ -42,6 +42,9 @@ $$
 
 For example, `l_mode_threshold_margin = 1.2` ensures that `p_l_h_threshold_mw` is at least $1.2\times$ greater than the separatrix power `p_plasma_separatrix_mw`.
 
+
+**It is recommended to use the H-mode constraint `icc = 15` at all times unless explicitly trying to enforce L-mode in which case `icc = 22` is used.**
+
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 ### Use the injected power reduced divertor power.