Not that libfprint is long to write, but in case we'll ever change the basename, we do it once.
Meson files are normally using 4-spaces to indent and functions use first parameter on the same line while others at next indentation level, not following the parenthesis indentation. So adapt libfprint to follow the meson standard.
Split the introduction into separate chapters, add filler documentation for async functions, fix mismatched function arguments.
