Add basic abortsignal example

[connyay]

Showing how to apply timeouts to fetch requests

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 2 untouched benchmarks

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_{Comparing connyay:cjh-abort-signal (87324cc) with main (417576c)}

[guybedford]

Amazing, thanks for sharing the example for this one.