Fix some typos, grammar and style in docs and comments

The portions fixing the documentation are backpatched where needed.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20210210235557.GQ20012@telsasoft.com
backpatch-through: 9.6

doc/src/sgml/charset.sgml

@@ -619,7 +619,7 @@ SELECT * FROM test1 ORDER BY a || b COLLATE "fr_FR";
     name such as <literal>de_DE</literal> can be considered unique
     within a given database even though it would not be unique globally.
     Use of the stripped collation names is recommended, since it will
-    make one less thing you need to change if you decide to change to
+    make one fewer thing you need to change if you decide to change to
     another database encoding.  Note however that the <literal>default</literal>,
     <literal>C</literal>, and <literal>POSIX</literal> collations can be used regardless of
     the database encoding.

doc/src/sgml/pageinspect.sgml

@@ -211,7 +211,7 @@ test=# SELECT tuple_data_split('pg_class'::regclass, t_data, t_infomask, t_infom
      </para>
      <para>
       If <parameter>do_detoast</parameter> is <literal>true</literal>,
-      attribute that will be detoasted as needed. Default value is
+      attributes will be detoasted as needed. Default value is
       <literal>false</literal>.
      </para>
     </listitem>

doc/src/sgml/protocol.sgml

@@ -6922,8 +6922,8 @@ Delete
 </term>
 <listitem>
 <para>
-                Identifies the following TupleData message as a old tuple.
+                Identifies the following TupleData message as an old tuple.
-                This field is present if the table in which the delete has
+                This field is present if the table in which the delete
                 happened has REPLICA IDENTITY set to FULL.
 </para>
 </listitem>

doc/src/sgml/ref/create_type.sgml

@@ -790,7 +790,7 @@ CREATE TYPE <replaceable class="parameter">name</replaceable>
    Before <productname>PostgreSQL</productname> version 8.3, the name of
    a generated array type was always exactly the element type's name with one
    underscore character (<literal>_</literal>) prepended.  (Type names were
-   therefore restricted in length to one less character than other names.)
+   therefore restricted in length to one fewer character than other names.)
    While this is still usually the case, the array type name may vary from
    this in case of maximum-length names or collisions with user type names
    that begin with underscore.  Writing code that depends on this convention

doc/src/sgml/ref/drop_index.sgml

@@ -45,7 +45,7 @@ DROP INDEX [ CONCURRENTLY ] [ IF EXISTS ] <replaceable class="parameter">name</r
      <para>
       Drop the index without locking out concurrent selects, inserts, updates,
       and deletes on the index's table.  A normal <command>DROP INDEX</command>
-      acquires exclusive lock on the table, blocking other accesses until the
+      acquires an exclusive lock on the table, blocking other accesses until the
       index drop can be completed.  With this option, the command instead
       waits until conflicting transactions have completed.
      </para>

doc/src/sgml/rules.sgml

@@ -1266,7 +1266,7 @@ CREATE [ OR REPLACE ] RULE <replaceable class="parameter">name</replaceable> AS
 <para>
     The query trees generated from rule actions are thrown into the
     rewrite system again, and maybe more rules get applied resulting
-    in more or less query trees.
+    in additional or fewer query trees.
     So a rule's actions must have either a different
     command type or a different result relation than the rule itself is
     on, otherwise this recursive process will end up in an infinite loop.