Refine comment in last commit, 24ebadc (thanks @mbeutel)

include/lest/lest.hpp

@@ -559,7 +559,8 @@ inline std::string transformed( char chr )
             return tr.str;
     }
 
-    auto unprintable = [](char c){ return 0 <= static_cast<signed char>(c) && c < ' '; };   // the cast is necessary on architectures where char is unsigned
+    // The cast below helps suppress warnings ("-Wtype-limits" on GCC) on architectures where `char` is unsigned.
+    auto unprintable = [](char c){ return 0 <= static_cast<signed char>(c) && c < ' '; };
 
     auto to_hex_string = [](char c)
     {

include/lest/lest_cpp03.hpp

@@ -614,7 +614,11 @@ inline void inform( location where, text expr )
 
 // Expression decomposition:
 
-inline bool unprintable( char c ) { return 0 <= static_cast<signed char>(c) && c < ' '; }  // the cast is necessary on architectures where char is unsigned
+inline bool unprintable( char c )
+{
+    // The cast helps suppress warnings ("-Wtype-limits" on GCC) on architectures where `char` is unsigned.
+    return 0 <= static_cast<signed char>(c) && c < ' ';
+}
 
 inline std::string to_hex_string(char c)
 {