Extra indentation in first line

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/10/static/textsearch-features.html
Description:

Hello,

In some queries there is an extra indentation. For example:

SELECT to_tsquery('fat') <-> to_tsquery('cat | rat');
?column?
-----------------------------------
'fat' <-> 'cat' | 'fat' <-> 'rat'

But there are no indentation (it's correct) here:

SELECT ts_rewrite('a & b'::tsquery,
'SELECT t,s FROM aliases WHERE ''a & b''::tsquery @>
t');
ts_rewrite
------------
'b' & 'c'

It seems that there are no such indentations within .sgml files.