Underlined text
Adds a Unicode combining low line (U+0332) after every character so the text appears underlined without HTML or markdown.
T̲h̲i̲s̲ ̲i̲s̲ ̲u̲n̲d̲e̲r̲l̲i̲n̲e̲d̲.
U̲n̲d̲e̲r̲l̲i̲n̲e̲
Underline every character with a Unicode combining mark.