docs: move paragraph closing tag

The pre-tag right before is a block-level tag, which means it implicitly
terminates the paragraph. So there's no paragraph to close after this.
Instead, move the paragraph-closing before the pre-tag, to explicitly
close the paragraph.

Fixes: 41b3eb08d9 "docs: update meson docs for windows"
Acked-by: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3431>

docs/meson.html

@@ -290,10 +290,11 @@ will never find libllvm.so.
 There is also a <code>-Dcmake_module_path</code> option in this meson version,
 which points to the root of an alternative installation (the prefix). For
 example:
+</p>
 <pre>
         meson builddir -Dcmake_module_path=/home/user/mycmake/prefix
 </pre>
-</p></dd>
+</dd>
 
 <dd><p>
 As of meson 0.49.0 meson also has the concept of a