Safari doesn't support Regex lookback

[Will Garrett]

When sorting, the table headers can break on Safari. This is due to unsupported regex in the TableHeader component (onisAscending).

Same issue in Explorer: edge/explorer#157

See image for example:
https://cdn.discordapp.com/attachments/876766057153560586/968546158567899156/unknown.png

Here's a thread about the issue/potential fix
https://stackoverflow.com/questions/51568821/works-in-chrome-but-breaks-in-safari-invalid-regular-expression-invalid-group