two-bucket: Do not specify any types in description
two-bucket: Do not specify any types in description

The description currently specifies that buckets are represented, in
both the input and the output, as strings.

This seems overly constraining. Consider those tracks that wish to
represent these buckets as variants of a tagged union or of an enum for
the purpose of better type safety. These tracks have these options in
order to do so:

* Accept the problem-specifications README as is, but act in
  contravention of it. But it is confusing if the README contradicts the
  tests.
* Create a custom description.md. But this is a little unfortunate
  because only two lines need to change, and it adds extra maintenance
  burden to have to maintain the custom description.md. Consider that if
  this description.md changes, the changes will probably need to be
  copied to each custom description.md
* Add to .meta/hints.md saying something to the effect of "ha ha ignore
  the above text about using Strings, we're using tagged unions / enums"
  so that this will be appended to the description. But it seems too
  strange to have a README contradict itself.
* Other solution I did not think of.

Thus, it seems it is best to remove the specification of the buckets as
a string so as to allow the flexibility.

For the purpose of consistency, all other types have been removed as
well, otherwise it would invite (very reasonable) questions about why
all inputs/outputs except the buckets have types given.

It is surmised that this leads to no real loss, because it should be
obvious that sizes, number of moves, and number of liters are all
numeric values.

https://github.com/exercism/problem-specifications/pull/990

petertseng/exercism-rust,sacherjj/rust,sacherjj/rust,sacherjj/rust,petertseng/exercism-rust,exercism/xrust,exercism/xrust,petertseng/exercism-rust