Move test of macro-generated macro with linebreak to snapshot

Author: dtolnay

src/test/rustdoc/macro-generated-macro.macro_linebreak_pre.html

@@ -0,0 +1,6 @@
+<pre class="rust macro"><code><span class="macro">macro_rules!</span> <span class="ident">linebreak</span> {
+    (
+        <span class="op">&lt;</span><span class="op">=</span> <span class="number">0</span> <span class="number">1</span> <span class="number">2</span> <span class="number">3</span> <span class="number">4</span> <span class="number">5</span> <span class="number">6</span> <span class="number">7</span> <span class="number">8</span> <span class="number">9</span> <span class="number">10</span> <span class="number">11</span> <span class="number">12</span> <span class="number">13</span> <span class="number">14</span> <span class="number">15</span> <span class="number">16</span> <span class="number">17</span> <span class="number">18</span> <span class="number">19</span> <span class="number">20</span> <span class="number">21</span> <span class="number">22</span> <span class="number">23</span> <span class="number">24</span> <span class="number">25</span>
+        <span class="number">26</span> <span class="number">27</span> <span class="number">28</span> =&gt;
+    ) =&gt; { ... };
+}</code></pre>

src/test/rustdoc/macro-generated-macro.rs

@@ -20,10 +20,5 @@ make_macro!(attributes #![no_std] #[cfg(feature = "alloc")]);
 // @has - //pre '(<= fn {} () { foo[0] } =>) => { ... };'
 make_macro!(groups fn {}() {foo[0]});
 
-// @has macro_generated_macro/macro.linebreak.html //pre 'macro_rules! linebreak {'
-// @has - //pre '    ('
-// @has - //pre '        <= 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25'
-// @has - //pre '        26 27 28 =>'
-// @has - //pre '    ) => { ... };'
-// @has - //pre '};'
+// @snapshot macro_linebreak_pre macro_generated_macro/macro.linebreak.html //pre
 make_macro!(linebreak 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28);