Virtualized renderer for syntax higlighter

[erykpiast]

Syntax highlighting of long files (like >1000 lines) may significantly decrease framerate. There is a package called react-syntax-highlighter-virtualized-renderer created to resolve exactly this issue, but it needs some fine-tuning. At the moment line numbers don't work with this renderer.

There is an issue open for this, must be resolved. PR seems doable.

[erykpiast]

There is good but also bad news.
The good one: line numbers are not an issue anymore! They're rendered as a part of the line, so it works perfectly with the virtualized renderer.
The bad: modified files are displayed with a different viewer, which doesn't support the linked package. It may (but doesn't have to) become a truth for added and removed packages as well (after resolving #233).