Bot version parsing in bot regexes is consistently done using `[\d.]+`.

In particular, the following changes are made:

- drop wrapper parentheses, where it is used, as the bot version is not
  exposed by the parser, and there is inconsistent use of grouping
  parentheses in the various regexes;
- `[\d+.]` is assumed to be a typo picked up from the use of `\d+.`
  outside character classes;
- `[\d+\.]` additionally uses a superfluous escape on the dot, which is
  not needed inside character classes;
- plain `\d` or `[0-9]` are replaced with the common expression, as they
  will match the same agent strings, but include more of the version
  string in the match–mainly, this drives consistency;

The main change that should arise here is that the plus character will
no longer be recognised as part of the bot/version match. The tests
don't suggest that this will be an issue. (If needed, the `+` can be
brought back, while keeping consistency)

Given that the groupings don't have a meaning, there's little point in
keeping them as part of the regexes. In addition, superfluous
parentheses are dropped.

The wildcard matches extend the match, but don't add value as the match
is already made at that point.

This avoids the need to escape the dash in character classes.