Fix a number of typos

Author: Liudmila Mantrova <l.mantrova@postgrespro.ru>

doc/src/sgml/cube.sgml

@@ -190,7 +190,7 @@
         n = 2 * k - 1 means lower bound of <replaceable>k</replaceable>-th
         dimension, n = 2 * k means upper bound of
         <replaceable>k</replaceable>-th dimension.  Negative
-        <replaceable>n</replaceable> denotes inversed value of corresponding
+        <replaceable>n</replaceable> denotes the inverse value of the corresponding
         positive coordinate.  This operator is designed for KNN-GiST support.
       </entry>
      </row>

doc/src/sgml/pgtrgm.sgml

@@ -168,15 +168,15 @@
    greatest similarity between the first string and any substring of the second
    string.  However, this function does not add padding to the boundaries of
    the extent.  Thus, the number of additional characters present in the
-   second string is not considered, except for the mismatched word boundry.
+   second string is not considered, except for the mismatched word boundaries.
   </para>
 
   <para>
    At the same time, <function>strict_word_similarity(text, text)</function>
-   selects extent of words in the second string.  In the example above,
+   selects an extent of words in the second string.  In the example above,
    <function>strict_word_similarity(text, text)</function> would select the
-   extent of single word <literal>'words'</literal>, whose set of trigrams is
-   <literal>{"  w"," wo","wor","ord","rds","ds "}</literal>
+   extent of a single word <literal>'words'</literal>, whose set of trigrams is
+   <literal>{"  w"," wo","wor","ord","rds","ds "}</literal>.
 
 <programlisting>
 # SELECT strict_word_similarity('word', 'two words'), similarity('word', 'words');

doc/src/sgml/ref/pgbench.sgml

@@ -1215,7 +1215,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
      </row>
      <row>
       <entry><literal>-</literal></entry>
-      <entry>substraction</entry>
+      <entry>subtraction</entry>
       <entry><literal>3 - 2.0</literal></entry>
       <entry><literal>1.0</literal></entry>
      </row>

doc/src/sgml/release-11.sgml

@@ -1083,7 +1083,7 @@ same commits as above
 -->
 
        <para>
-        Allow vacuum to avoid unnecesary index scans (Masahiko Sawada,
+        Allow vacuum to avoid unnecessary index scans (Masahiko Sawada,
         Alexander Korotkov)
        </para>
       </listitem>
@@ -1594,7 +1594,7 @@ same commits as above
 -->
 
        <para>
-        Allow replication slots to be advanced programatically, rather
+        Allow replication slots to be advanced programmatically, rather
         than be consumed by subscribers (Petr Jelinek)
        </para>
 
@@ -1704,7 +1704,7 @@ same commits as above
 
        <para>
         Allow <command>ALTER INDEX</command> to set statistics-gathering
-        targets for expression indexes (Alexander Korotkov, Adrien nayrat)
+        targets for expression indexes (Alexander Korotkov, Adrien Nayrat)
        </para>
 
        <para>