add reason to comment about variable not able to be checekd

Author: peverwhee

src/data/write_init_files.py

@@ -1255,7 +1255,7 @@ def write_phys_check_subroutine(outfile, host_dict, host_vars, host_imports,
             call_str += "min_difference, min_relative_value, is_first, diff_found)"
         else:
             # For check field, don't endrun
-            call_str = f"! do nothing - '{var_locname}' can't be checked against a file"
+            call_str = f"! do nothing - '{var_locname}' can't be checked against a file because {reason}"
         # end if
         # Add string to dictionary:
         call_string_dict[call_string_key] = call_str

test/unit/python/sample_files/write_init_files/physics_inputs_simple.F90

@@ -337,7 +337,7 @@ subroutine physics_check_data(file_name, suite_names, timestep, min_difference,
                           min_relative_value, is_first, diff_found)
 
                   case ('scalar_variable_llama')
-                     ! do nothing - 'var_nodim' can't be checked against a file
+                     ! do nothing - 'var_nodim' can't be checked against a file because var_nodim has no horizontal dimension
 
                   end select !check variables
                   if (diff_found) then