message: Support Ruby placeholders
  Now that GNU gettext 0.21 supports Ruby natively, so should Poedit. And
  both format-ruby support and generic highlighting of Ruby's %{foo}
  syntax.
diff: @@ -183,8 +183,12 @@ std::wregex RE_PHP_FORMAT(LR"(%(\d+\$)?[-+]{0,2}([ 0]|'.)?-?\d*(\..?\d+)?[%bcdeE
  std::wregex RE_C_FORMAT(LR"(%(\d+\$)?[-+ #0]{0,5}(\d+|\*)?(\.(\d+|\*))?(hh|ll|[hljztL])?[%csdioxXufFeEaAgGnp])",
  std::regex_constants::ECMAScript | std::regex_constants::optimize);
  -// variables expansion for %foo% (Twig), {foo} and {{foo}}
  -std::wregex RE_COMMON_PLACEHOLDERS(LR"((%[0-9a-zA-Z_.-]+%)|(\{[0-9a-zA-Z_.-]+\})|(\{\{[0-9a-zA-Z_.-]+\}\}))",
  +// ruby-format per https://ruby-doc.org/core-2.7.1/Kernel.html#method-i-sprintf
  +std::wregex RE_RUBY_FORMAT(LR"(%(\d+\$)?[-+ #0]{0,5}(\d+|\*)?(\.(\d+|\*))?(hh|ll|[hljztL])?[%csdioxXufFeEaAgGnp])",
  + std::regex_constants::ECMAScript | std::regex_constants::optimize);
  +
  +// variables expansion for %foo% (Twig), %{foo} (Ruby), {foo} and {{foo}}
  +std::wregex RE_COMMON_PLACEHOLDERS(LR"((%[0-9a-zA-Z_.-]+%)|(%?\{[0-9a-zA-Z_.-]+\})|(\{\{[0-9a-zA-Z_.-]+\}\}))",
  std::regex_constants::ECMAScript | std::regex_constants::optimize);
  } // anonymous namespace
  @@ -227,6 +231,11 @@ SyntaxHighlighterPtr SyntaxHighlighter::ForItem(const CatalogItem& item)
  static auto c_format = std::make_shared<RegexSyntaxHighlighter>(RE_C_FORMAT, TextKind::Format);
  all->Add(c_format);
  }
  + else if (formatFlag == "ruby")
  + {
  + static auto ruby_format = std::make_shared<RegexSyntaxHighlighter>(RE_RUBY_FORMAT, TextKind::Format);
  + all->Add(ruby_format);
  + }
  // basic higlighting has highest priority, so should come last in the order:
  all->Add(basic);
  