doc: Clean up title case use

Note: Following existing practice, titles of formalpara and step are
not titlecased.

doc/src/sgml/ref/create_table.sgml

@@ -2078,7 +2078,7 @@ CREATE TABLE cities_partdef
   </refsect2>
 
   <refsect2>
-   <title>Non-deferred Uniqueness Constraints</title>
+   <title>Non-Deferred Uniqueness Constraints</title>
 
    <para>
     When a <literal>UNIQUE</literal> or <literal>PRIMARY KEY</literal> constraint is
@@ -2166,7 +2166,7 @@ CREATE TABLE cities_partdef
   </refsect2>
 
   <refsect2>
-   <title>Zero-column Tables</title>
+   <title>Zero-Column Tables</title>
 
    <para>
     <productname>PostgreSQL</productname> allows a table of no columns

doc/src/sgml/ref/pg_rewind.sgml

@@ -273,7 +273,7 @@ GRANT EXECUTE ON function pg_catalog.pg_read_binary_file(text, bigint, bigint, b
   </para>
 
   <refsect2>
-   <title>How it works</title>
+   <title>How It Works</title>
 
    <para>
     The basic idea is to copy all file system-level changes from the source

doc/src/sgml/ref/pgbench.sgml

@@ -836,7 +836,7 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
   <title>Notes</title>
 
  <refsect2>
-  <title>What is the <quote>Transaction</quote> Actually Performed in <application>pgbench</application>?</title>
+  <title>What Is the <quote>Transaction</quote> Actually Performed in <application>pgbench</application>?</title>
 
   <para>
    <application>pgbench</application> executes test scripts chosen randomly
@@ -1151,7 +1151,7 @@ SELECT 2 AS two, 3 AS three \gset p_
  </refsect2>
 
  <refsect2 id="pgbench-builtin-operators">
-  <title>Built-In Operators</title>
+  <title>Built-in Operators</title>
 
   <para>
    The arithmetic, bitwise, comparison and logical operators listed in
@@ -1161,7 +1161,7 @@ SELECT 2 AS two, 3 AS three \gset p_
   </para>
 
   <table id="pgbench-operators">
-   <title>pgbench Operators by increasing precedence</title>
+   <title>pgbench Operators by Increasing Precedence</title>
    <tgroup cols="4">
     <thead>
      <row>

doc/src/sgml/ref/pgtesttiming.sgml

@@ -86,7 +86,7 @@
   <title>Usage</title>
 
  <refsect2>
-  <title>Interpreting results</title>
+  <title>Interpreting Results</title>
 
   <para>
    Good results will show most (>90%) individual timing calls take less than
@@ -116,7 +116,7 @@ Histogram of timing durations:
 
  </refsect2>
  <refsect2>
-  <title>Measuring executor timing overhead</title>
+  <title>Measuring Executor Timing Overhead</title>
 
   <para>
    When the query executor is running a statement using
@@ -145,7 +145,7 @@ EXPLAIN ANALYZE SELECT COUNT(*) FROM t;
  </refsect2>
 
  <refsect2>
-  <title>Changing time sources</title>
+  <title>Changing Time Sources</title>
   <para>
    On some newer Linux systems, it's possible to change the clock source used
    to collect timing data at any time.  A second example shows the slowdown
@@ -223,7 +223,7 @@ Histogram of timing durations:
  </refsect2>
 
  <refsect2>
-  <title>Clock hardware and timing accuracy</title>
+  <title>Clock Hardware and Timing Accuracy</title>
 
   <para>
    Collecting accurate timing information is normally done on computers using

doc/src/sgml/ref/pgupgrade.sgml

@@ -450,7 +450,7 @@ pg_upgrade.exe
    </step>
 
    <step id="pgupgrade-step-replicas">
-    <title>Upgrade Streaming Replication and Log-Shipping standby servers</title>
+    <title>Upgrade streaming replication and log-shipping standby servers</title>
 
     <para>
      If you used link mode and have Streaming Replication (see <xref
@@ -617,7 +617,7 @@ rsync --archive --delete --hard-links --size-only --no-inc-recursive /vol1/pg_tb
    </step>
 
    <step>
-    <title>Post-Upgrade processing</title>
+    <title>Post-upgrade processing</title>
 
     <para>
      If any post-upgrade processing is required, pg_upgrade will issue

doc/src/sgml/ref/postgres-ref.sgml

@@ -391,7 +391,7 @@ PostgreSQL documentation
    </refsect2>
 
    <refsect2>
-    <title>Semi-internal Options</title>
+    <title>Semi-Internal Options</title>
 
     <para>
      The options described here are used