doc: Avoid writing in first-person form

This rewrites the few places where first-person form was used, and
replaces with wording more in line with the rest of the documentation.

While there, the section on editing PO files is split between what
to edit with, and how to edit, as well as add a missing colon.

Author: Daniel Gustafsson <daniel@yesql.se>
Reported-by: wolakk@gmail.com
Discussion: https://postgr.es/m/166692508416.630.9910522387468316027@wrigleys.postgresql.org

doc/src/sgml/cube.sgml

@@ -537,7 +537,7 @@ SELECT c FROM test ORDER BY c ~> 3 DESC LIMIT 5;
   <title>Defaults</title>
 
   <para>
-   I believe this union:
+   This union:
   </para>
 <programlisting>
 select cube_union('(0,5,2),(2,3,1)', '0');
@@ -548,7 +548,7 @@ cube_union
 </programlisting>
 
    <para>
-    does not contradict common sense, neither does the intersection
+    does not contradict common sense, neither does the intersection:
    </para>
 
 <programlisting>
@@ -560,8 +560,8 @@ cube_inter
 </programlisting>
 
    <para>
-    In all binary operations on differently-dimensioned cubes, I assume the
-    lower-dimensional one to be a Cartesian projection, i. e., having zeroes
+    In all binary operations on differently-dimensioned cubes,
+    the lower-dimensional one is assumed to be a Cartesian projection, i. e., having zeroes
     in place of coordinates omitted in the string representation. The above
     examples are equivalent to:
    </para>

doc/src/sgml/nls.sgml

@@ -205,13 +205,16 @@ make update-po
    <para>
     The PO files can be edited with a regular text editor. There are also
     several specialized editors for PO files which can help the process with
-    translation specific features.  The
-    translator should only change the area between the quotes after
-    the msgstr directive, add comments, and alter the fuzzy flag.
-    There is (unsurprisingly) a PO mode for Emacs, which I find quite
+    translation specific features.
+    There is (unsurprisingly) a PO mode for Emacs, which can be quite
     useful.
    </para>
 
+   <para>
+    The translator should only change the area between the quotes after
+    the msgstr directive, add comments, and alter the fuzzy flag.
+   </para>
+
    <para>
     The PO files need not be completely filled in.  The software will
     automatically fall back to the original string if no translation

doc/src/sgml/pgcrypto.sgml

@@ -415,8 +415,8 @@ gen_salt(type text [, iter_count integer ]) returns text
     <listitem>
      <para>
       <literal>crypt-bf</literal> numbers are taken using a simple program that
-      loops over 1000 8-character passwords.  That way I can show the speed
-      with different numbers of iterations.  For reference: <literal>john
+      loops over 1000 8-character passwords.  That way the speed
+      with different numbers of iterations can be shown.  For reference: <literal>john
       -test</literal> shows 13506 loops/sec for <literal>crypt-bf/5</literal>.
       (The very small
       difference in results is in accordance with the fact that the