command_line/options: Handle better displaying the set name in option…

…Set_t::displayHelp()

It is known by the author that the upper-casing of the meta name will break if given non-ASCII characters, but C++ does not provide a good means to solve this for now.

impl/command_line/options.cxx

@@ -142,8 +142,8 @@ namespace substrate::commandLine
 	void optionSet_t::displayHelp(const size_t padding) const noexcept
 	{
 		console.writeln();
-		// XXX: Need to capitalise the first letter.
-		console.writeln(metaName(), "s:"sv);
+		const auto &metaName{_metaName.substr(1)};
+		console.writeln(std::toupper(_metaName[0], std::locale::classic()), metaName, "s:"sv);
 		for (const auto &alternation : _alternations)
 		{
 			console.writeln('\t', alternation.displayName(), nullptr);