Doc: tweak examples to silence line-too-long PDF build warnings.

In one or two places it seemed reasonable to modify the example so as
to shorten its output slightly; but for the most part I just added a
&zwsp; after 67 characters, which is the most we can fit on a line
of monospace text in A4 format.

Discussion: https://postgr.es/m/6916.1589146280@sss.pgh.pa.us

doc/src/sgml/syntax.sgml

@@ -2317,9 +2317,9 @@ SELECT ARRAY[]::integer[];
    bracketed) subquery. For example:
 <programlisting>
 SELECT ARRAY(SELECT oid FROM pg_proc WHERE proname LIKE 'bytea%');
-                                 array
------------------------------------------------------------------------
- {2011,1954,1948,1952,1951,1244,1950,2005,1949,1953,2006,31,2412,2413}
+                              array
+------------------------------------------------------------------
+ {2011,1954,1948,1952,1951,1244,1950,2005,1949,1953,2006,31,2412}
 (1 row)
 
 SELECT ARRAY(SELECT ARRAY[i, i*2] FROM generate_series(1,5) AS a(i));