We aim at improving the readability and maintainability of Options.td,
and in particular its handling of 'Flags', by
- limiting the extent of 'let Flags = [...] in {'s, and
- adding closing comments to matching '}'s.
- being more consistent about empty lines around 'let Flags' and '}'.
More concretely,
- we do not let a 'let Flags' span across several headline comments. When all 'def's in two consecutive headlines share the same flags, we stil close and start a new 'let Flags' at the intermediate headline.
- when a 'let Flags' span just one or two 'def's, set 'Flags' within the 'def's instead.
- we remove nested 'let Flags'.
Note that nested 'let Flags' can be quite confusing, especially when
the outer was started long before the inner. Moving a 'def' out of the
inner 'let Flags' and setting 'Flags' within the 'def' will not have the
intended effect, as those flags will be overridden by the outer
'let Flags'.