doc: Fix typos in documentation

This fixes a set of typos introduced during the v18 development
cycle.

Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/7038B4C5-2742-42B1-A8F0-0FFEAECF02A7@yesql.se

doc/src/sgml/amcheck.sgml

@@ -201,7 +201,7 @@ ORDER BY c.relpages DESC LIMIT 10;
      <para>
       <function>gin_index_check</function> tests that its target GIN index
       has consistent parent-child tuples relations (no parent tuples
-      require tuple adjustement) and page graph respects balanced-tree
+      require tuple adjustment) and page graph respects balanced-tree
       invariants (internal pages reference only leaf page or only internal
       pages).
      </para>

doc/src/sgml/protocol.sgml

@@ -238,7 +238,7 @@
       <entry>PostgreSQL 18 and later</entry>
       <entry>Current latest version. The secret key used in query
         cancellation was enlarged from 4 bytes to a variable length field. The
-        BackendKeyData message was changed to accomodate that, and the CancelRequest
+        BackendKeyData message was changed to accommodate that, and the CancelRequest
         message was redefined to have a variable length payload.
       </entry>
       </row>

doc/src/sgml/ref/initdb.sgml

@@ -543,7 +543,7 @@ PostgreSQL documentation
        </para>
        <para>
         Note that if <option>--no-sync-data-files</option> is used in
-        conjuction with <option>--sync-method=syncfs</option>, some or all of
+        conjunction with <option>--sync-method=syncfs</option>, some or all of
         the aforementioned files and directories will be synchronized because
         <literal>syncfs</literal> processes entire file systems.
        </para>

doc/src/sgml/system-views.sgml

@@ -4070,7 +4070,7 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
    <productname>PostgreSQL</productname> itself and memory allocated
    by extensions using the mechanisms detailed in
    <xref linkend="xfunc-shared-addin" />. This view will output multiple rows
-   for each of the shared memory segments provided that they are spread accross
+   for each of the shared memory segments provided that they are spread across
    multiple NUMA nodes. This view should not be queried by monitoring systems
    as it is very slow and may end up allocating shared memory in case it was not
    used earlier.