Bump syn from 2.0.14 to 2.0.15 (#2820)

Bumps [syn](https://github.com/dtolnay/syn) from 2.0.14 to 2.0.15.
<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>2.0.15</h2>
<ul>
<li>Ensure <code>Type::Tuple</code> of length 1 prints as a tuple even if trailing comma is not provided in the Punctuated (<a href="https://redirect.github.com/dtolnay/syn/issues/1444">#1444</a>, thanks <a href="https://github.com/Fancyflame"><code>@​Fancyflame</code></a>)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="3da56a712a"><code>3da56a7</code></a> Release 2.0.15</li>
<li><a href="2b7ba23559"><code>2b7ba23</code></a> Merge pull request <a href="https://redirect.github.com/dtolnay/syn/issues/1444">#1444</a> from Fancyflame/master</li>
<li><a href="03e4f217bd"><code>03e4f21</code></a> fix TypeTuple::to_tokens may result in TypeParen</li>
<li><a href="0f78bdf2eb"><code>0f78bdf</code></a> Update test suite to nightly-2023-04-13</li>
<li><a href="6536786900"><code>6536786</code></a> Ignore unnecessary_box_returns pedantic clippy lint</li>
<li>See full diff in <a href="https://github.com/dtolnay/syn/compare/2.0.14...2.0.15">compare view</a></li>
</ul>
</details>
<br />


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</details>

Cargo.lock

@@ -495,7 +495,7 @@ version = "0.16.0"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
  "synstructure 0.13.0",
 ]
 
@@ -784,7 +784,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -1109,7 +1109,7 @@ dependencies = [
  "proc-macro2",
  "quote",
  "scratch",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -1126,7 +1126,7 @@ checksum = "2345488264226bf682893e25de0769f3360aac9957980ec49361b083ddaa5bc5"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -1601,7 +1601,7 @@ checksum = "89ca545a94061b6365f2c7355b4b32bd20df3ff95f02da9329b34ccc3bd6ee72"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -2798,7 +2798,7 @@ dependencies = [
  "proc-macro-crate",
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -3634,7 +3634,7 @@ checksum = "291a097c63d8497e00160b166a967a4a79c64f3facdd01cbd7502231688d77df"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -3656,7 +3656,7 @@ checksum = "bcec881020c684085e55a25f7fd888954d56609ef363479dc5a1305eb0d40cab"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]
@@ -3980,9 +3980,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.14"
+version = "2.0.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fcf316d5356ed6847742d036f8a39c3b8435cac10bd528a4bd461928a6ab34d5"
+checksum = "a34fcf3e8b60f57e6a14301a2e916d323af98b0ea63c599441eec8558660c822"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -4009,7 +4009,7 @@ checksum = "285ba80e733fac80aa4270fbcdf83772a79b80aa35c97075320abfee4a915b06"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
  "unicode-xid",
 ]
 
@@ -4121,7 +4121,7 @@ checksum = "f9456a42c5b0d803c8cd86e73dd7cc9edd429499f37a3550d286d5e86720569f"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.14",
+ "syn 2.0.15",
 ]
 
 [[package]]

boa_macros/Cargo.toml

@@ -13,6 +13,6 @@ proc-macro = true
 
 [dependencies]
 quote = "1.0.26"
-syn = { version = "2.0.14", features = ["full"] }
+syn = { version = "2.0.15", features = ["full"] }
 proc-macro2 = "1.0"
 synstructure = "0.13"