build(deps): Bump syn from 2.0.69 to 2.0.70 (#569)

Bumps [syn](https://github.com/dtolnay/syn) from 2.0.69 to 2.0.70.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/dtolnay/syn/releases">syn's
releases</a>.</em></p>
<blockquote>
<h2>2.0.70</h2>
<ul>
<li>Improve parenthesization of closures, jumps, ranges, chained
comparisons, and let (<a
href="https://redirect.github.com/dtolnay/syn/issues/1694">#1694</a>, <a
href="https://redirect.github.com/dtolnay/syn/issues/1695">#1695</a>, <a
href="https://redirect.github.com/dtolnay/syn/issues/1698">#1698</a>, <a
href="https://redirect.github.com/dtolnay/syn/issues/1699">#1699</a>, <a
href="https://redirect.github.com/dtolnay/syn/issues/1700">#1700</a>)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/dtolnay/syn/commit/5c67e2689791db44258d99402ae6d05b1898d9a3"><code>5c67e26</code></a>
Release 2.0.70</li>
<li><a
href="https://github.com/dtolnay/syn/commit/935c1e1817d411a02d09d2315ed533df12f70ace"><code>935c1e1</code></a>
Configure out more full-only expression kinds in print_expr</li>
<li><a
href="https://github.com/dtolnay/syn/commit/e664375b4981637a490f1f30dd252536371ef2cc"><code>e664375</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1704">#1704</a>
from dtolnay/fixup</li>
<li><a
href="https://github.com/dtolnay/syn/commit/f1daf234e942ffda27ed45ec67aa6cd984081c2a"><code>f1daf23</code></a>
Enable expression fixups in 'derive' mode</li>
<li><a
href="https://github.com/dtolnay/syn/commit/678dbc2e50904de7b80f10f4d355be5536a8bceb"><code>678dbc2</code></a>
Update test suite to nightly-2024-07-08</li>
<li><a
href="https://github.com/dtolnay/syn/commit/628e2f7003d17ae0c02d0da076577001e62015a3"><code>628e2f7</code></a>
Ignore needless_update clippy lint</li>
<li><a
href="https://github.com/dtolnay/syn/commit/c3e378cdda142d83f14055661001d39533199f3f"><code>c3e378c</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1703">#1703</a>
from dtolnay/cast</li>
<li><a
href="https://github.com/dtolnay/syn/commit/d47e532913bb9138cc47a6a3756aeead9ad2d08a"><code>d47e532</code></a>
Rearrange logic of FixupContext precedence methods</li>
<li><a
href="https://github.com/dtolnay/syn/commit/9809f716e3aa0b3223489860f29385afcd04b5f8"><code>9809f71</code></a>
Incorporate parenthesization of casts into FixupContext</li>
<li><a
href="https://github.com/dtolnay/syn/commit/ff022f529241e536c75ecd79ee155518723c1460"><code>ff022f5</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1702">#1702</a>
from dtolnay/preclet</li>
<li>Additional commits viewable in <a
href="https://github.com/dtolnay/syn/compare/2.0.69...2.0.70">compare
view</a></li>
</ul>
</details>
<br />


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