Fix some grammar errors in bloom.sgml

Discussion:  https://postgr.es/m/CAEepm%3D3sijpGr8tXdyz-7EJJZfhQHABPKEQ29gpnb7-XSy%2B%3D5A%40mail.gmail.com
Reported-by: Thomas Munro
Backpatch-through: 9.6

doc/src/sgml/bloom.sgml

@@ -51,8 +51,9 @@
     <term><literal>length</></term>
     <listitem>
      <para>
-      Length of each signature (index entry) in bits, it is rounded up to the nearest
-      multiple of <literal>16</>. The default is <literal>80</> bits and maximum is <literal>4096</literal>.
+      Length of each signature (index entry) in bits. It is rounded up to the
+      nearest multiple of <literal>16</>. The default is <literal>80</> bits
+      and the maximum is <literal>4096</>.
      </para>
     </listitem>
    </varlistentry>