Add borders for tables in TILs

[simonw]

e.g. on https://til.simonwillison.net/sqlite/simple-recursive-cte

And these others: https://til.simonwillison.net/tils/til?html__contains=%3Ctable&_sort_desc=updated_utc

[simonw]

https://til.simonwillison.net/svg/dynamic-line-chart is a better example:

[simonw]

This will do:

table {
  border-collapse: collapse;
}
th, td {
  padding: 0.3em;
  border: 1px solid #D3D3D3;
}
th {
  background-color: #eee;
}

[simonw]

Demo: https://til.simonwillison.net/svg/dynamic-line-chart