Link-error-test plugin finds unfulfilled links

[finanalyst]

• Link data is saved when parsing sources
• Target anchors created during rendering are saved
• LET compares link data and target data, and reports on mismatch
• The plugin was broken
• The format of the errors is converted into an HTML table and is better than the grid styling.
• A link to the error-report is placed in the About page.

[finanalyst]

The test deployment at new-raku/error-report is live