MathJax preview fix and improvements

[billti]

This fixes an issue with \braket where it was doubling up the entries. The preview today shows:

The fix was to replace physics with braket package. (Not sure why, will log a MathJax bug for that also).

The below two items I was playing with a week ago, but including here:

• Made the page render one kata at a time, and supports linking to a kata via the URL and forward/back navigation between katas without a page reload. (As on slow machines putting every kata on the one page was too slow)
• Converted to Preact to match the rest of our code, instead of manipulating DOM elements directly.

[billti]

This seems to be showing all of the changes from #1503 for some reason too. Will fix and repush.

[billti]

I'll just open a new PR on a new branch. Something's messed up.

[github-actions[bot]]

Benchmark for 1719fde

Click to view benchmark

| Test | Base | PR | % | |------|--------------|------------------|---| | Array append evaluation | 353.0±4.97µs | 352.6±2.49µs | -0.11% | | Array literal evaluation | 198.7±1.43µs | **180.5±2.75µs** | **-9.16%** | | Array update evaluation | 434.3±1.91µs | 434.4±2.16µs | +0.02% | | Core + Standard library compilation | 18.5±0.70ms | 18.7±0.80ms | +1.08% | | Deutsch-Jozsa evaluation | 5.1±0.04ms | 5.1±0.09ms | 0.00% | | Large file parity evaluation | 33.8±0.08ms | 33.8±0.38ms | 0.00% | | Large input file compilation | 12.4±0.53ms | 12.5±0.39ms | +0.81% | | Large input file compilation (interpreter) | 48.3±1.30ms | 47.9±1.26ms | -0.83% | | Large nested iteration | 34.4±0.37ms | 34.5±1.01ms | +0.29% | | Perform Runtime Capabilities Analysis (RCA) on Deutsch-Jozsa sample | 1560.4±36.42µs | 1563.0±72.73µs | +0.17% | | Perform Runtime Capabilities Analysis (RCA) on large file sample | **7.7±0.14ms** | 7.8±0.09ms | **+1.30%** | | Perform Runtime Capabilities Analysis (RCA) on teleport sample | 1437.5±45.74µs | 1442.6±99.00µs | +0.35% | | Perform Runtime Capabilities Analysis (RCA) on the core and std libraries | **27.1±0.18ms** | 27.6±0.26ms | **+1.85%** | | Teleport evaluation | 87.7±3.50µs | 89.1±3.47µs | +1.60% |