chore(deps): Bump syn from 2.0.23 to 2.0.25 (#17970)

Bumps [syn](https://github.com/dtolnay/syn) from 2.0.23 to 2.0.25.
<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>2.0.25</h2>
<ul>
<li>Support single identifier as unbraced const generic argument (<a
href="https://redirect.github.com/dtolnay/syn/issues/1483">#1483</a>)</li>
<li>Produce error message when LitStr::parse is used on a suffixed
string literal (<a
href="https://redirect.github.com/dtolnay/syn/issues/1484">#1484</a>)</li>
</ul>
<h2>2.0.24</h2>
<ul>
<li>Fix duplication of braces around const generic argument in non-full
mode (<a
href="https://redirect.github.com/dtolnay/syn/issues/1482">#1482</a>)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/dtolnay/syn/commit/026a38ccb0dbc0fcfbba21c718f5604e3225deec"><code>026a38c</code></a>
Release 2.0.25</li>
<li><a
href="https://github.com/dtolnay/syn/commit/4d7254398ce1d2faa90c8ad2ef1201072a0f75da"><code>4d72543</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1484">#1484</a>
from dtolnay/parsesuffix</li>
<li><a
href="https://github.com/dtolnay/syn/commit/d59afb25b739bd0cee1bb3add15064d918e429e1"><code>d59afb2</code></a>
Reject parse on LitStr containing suffix</li>
<li><a
href="https://github.com/dtolnay/syn/commit/7e8358abefb858ac59375e8dfcc2567f15a08306"><code>7e8358a</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1483">#1483</a>
from dtolnay/identgeneric</li>
<li><a
href="https://github.com/dtolnay/syn/commit/ed8d784eff614f564cd0daf52a622aaba6f81c19"><code>ed8d784</code></a>
Support single identifier as unbraced const generic argument</li>
<li><a
href="https://github.com/dtolnay/syn/commit/e523c3663601e0545aa96d34c2151782814419f0"><code>e523c36</code></a>
Directly call more specific expr ToTokens impl</li>
<li><a
href="https://github.com/dtolnay/syn/commit/24c48cdef661faee12d612a69c4e835060c3f5b6"><code>24c48cd</code></a>
Release 2.0.24</li>
<li><a
href="https://github.com/dtolnay/syn/commit/cefa056bab4f67a29ad4d3c208c3a76af5007360"><code>cefa056</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/syn/issues/1482">#1482</a>
from dtolnay/nonfullconstarg</li>
<li><a
href="https://github.com/dtolnay/syn/commit/a4fc6b113b3c3b8316d1fede7881b4b3bdd643e2"><code>a4fc6b1</code></a>
Fix duplication of braces around const generic argument in non-full
mode</li>
<li><a
href="https://github.com/dtolnay/syn/commit/d757cf4eb700a408bb3c005192af405049bff786"><code>d757cf4</code></a>
Update test suite to nightly-2023-07-07</li>
<li>Additional commits viewable in <a
href="https://github.com/dtolnay/syn/compare/2.0.23...2.0.25">compare
view</a></li>
</ul>
</details>
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