Better representations of errors

[zjhmale]

• Note for contribution to vscode-icons Add Idris Icons vscode-icons/vscode-icons#830
• Show problems panel directly instead of output channel. Pending on [RFC] Show Problems Panel API microsoft/vscode#22885
• Highlight Output Channel

Highlight Output Channel is pending on upstream issues:

microsoft/vscode#586
microsoft/vscode#11005

The original approach e3a1d6c to fix this can highlight messages in output channel indeed, but it will override some default behaviors of the output channel, e.g. we can no longer click the links inside output channel, even use registerDocumentLinkProvider

Another hacky approach html_views

[zjhmale]

We need more cute icons for idr, ibc and ipkg files, can you kindly offer some help here @be5invis? Thanks in advance 😄

[zjhmale]

Using a previewHtml is also a doable way but not good at designing and stylesheets.