Minor documentation fixes

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/tests/scripts/test_psa_constant_names.py b/tests/scripts/test_psa_constant_names.py
index 694e2a9..5de59c2 100755
--- a/tests/scripts/test_psa_constant_names.py
+++ b/tests/scripts/test_psa_constant_names.py
@@ -306,7 +306,7 @@
     return inputs
 
 def run_c(type_word, expressions, include_path=None, keep_c=False):
-    """Generate and run a program to print out numerical values for expressions."""
+    """Generate and run a program to print out numerical values of C expressions."""
     if type_word == 'status':
         cast_to = 'long'
         printf_format = '%ld'