Improve generated READMEs re: new bidi data

[mathiasbynens]

This part specifically:

// bidi-mirroring:

require('unicode-6.3.0/bidi-mirroring/');

→ There should be no trailing slash.

// bidi-brackets:

require('unicode-6.3.0/bidi-brackets/o/code-points');
require('unicode-6.3.0/bidi-brackets/o/symbols');
require('unicode-6.3.0/bidi-brackets/o/regex');

require('unicode-6.3.0/bidi-brackets/c/code-points');
require('unicode-6.3.0/bidi-brackets/c/symbols');
require('unicode-6.3.0/bidi-brackets/c/regex');

o → Open
c → Close

That way, it’s more readable, and also more in line with other property/script/block/category names.

[cscott]

Looks good to me.