Doc: improve libpq service-file docs, avoid overspecifying pathnames.

Clarify libpq.sgml's description of service file locations and
semantics.  Avoid use of backtick'ed pg_config calls to describe
paths; that doesn't work on Windows, and even on Unix it's an
idiom that not all readers may be instantly familiar with.

Don't overspecify the locations of include files, instead writing
only as much as you'd use in #include directives.  The previous text
in these places was incorrect for some installations, depending on
where "postgresql" is in the install path.

Our convention for referencing the user's home directory seems
to be "~", so change the one place that spelled it "$HOME".

install-windows.sgml follows the platform convention of spelling
file paths with "\", so change the one place that used "/".

Haiying Tang and Tom Lane

Discussion: https://postgr.es/m/162149020918.26174.7150424047314144297@wrigleys.postgresql.org

doc/src/sgml/config.sgml

@@ -10888,7 +10888,7 @@ LOG:  CleanUpLock: deleting: lock(0xb7acd844) id(24688,24696,0,0,0,1)
        <para>
         If LLVM has the required functionality, emit the data needed to allow
         <productname>perf</productname> to profile functions generated by JIT.
-        This writes out files to <filename>$HOME/.debug/jit/</filename>; the
+        This writes out files to <filename>~/.debug/jit/</filename>; the
         user is responsible for performing cleanup when desired.
         The default setting is <literal>off</literal>.
         This parameter can only be set at server start.

doc/src/sgml/install-windows.sgml

@@ -102,7 +102,7 @@
  <para>
   The tools for building using <productname>Visual C++</productname> or
   <productname>Platform SDK</productname> are in the
-  <filename>src/tools/msvc</filename> directory. When building, make sure
+  <filename>src\tools\msvc</filename> directory. When building, make sure
   there are no tools from <productname>MinGW</productname> or
   <productname>Cygwin</productname> present in your system PATH. Also, make
   sure you have all the required Visual C++ tools available in the PATH. In

doc/src/sgml/libpq.sgml

@@ -3829,8 +3829,9 @@ Oid PQftype(const PGresult *res,
        You can query the system table <literal>pg_type</literal> to
        obtain the names and properties of the various data types. The
        <acronym>OID</acronym>s of the built-in data types are defined
-       in the file <filename>include/server/catalog/pg_type_d.h</filename>
-       in the install directory.
+       in the file <filename>catalog/pg_type_d.h</filename>
+       in the <productname>PostgreSQL</productname>
+       installation's <filename>include</filename> directory.
       </para>
      </listitem>
     </varlistentry>
@@ -8091,26 +8092,30 @@ myEventProc(PGEventId evtId, void *evtInfo, void *passThrough)
   <para>
    The connection service file allows libpq connection parameters to be
    associated with a single service name. That service name can then be
-   specified by a libpq connection, and the associated settings will be
+   specified in a libpq connection string, and the associated settings will be
    used. This allows connection parameters to be modified without requiring
-   a recompile of the libpq application. The service name can also be
+   a recompile of the libpq-using application. The service name can also be
    specified using the <envar>PGSERVICE</envar> environment variable.
   </para>
 
   <para>
-   The connection service file can be a per-user service file
-   at <filename>~/.pg_service.conf</filename> or the location
-   specified by the environment variable <envar>PGSERVICEFILE</envar>,
-   or it can be a system-wide file
-   at <filename>`pg_config --sysconfdir`/pg_service.conf</filename> or in the directory
-   specified by the environment variable
-   <envar>PGSYSCONFDIR</envar>.  If service definitions with the same
-   name exist in the user and the system file, the user file takes
-   precedence.
+   Service names can be defined in either a per-user service file or a
+   system-wide file.  If the same service name exists in both the user
+   and the system file, the user file takes precedence.
+   By default, the per-user service file is located
+   at <filename>~/.pg_service.conf</filename>; this can be overridden by
+   setting the environment variable <envar>PGSERVICEFILE</envar>.
+   The system-wide file is named <filename>pg_service.conf</filename>.
+   By default it is sought in the <filename>etc</filename> directory
+   of the <productname>PostgreSQL</productname> installation
+   (use <literal>pg_config --sysconfdir</literal> to identify this
+   directory precisely).  Another directory, but not a different file
+   name, can be specified by setting the environment variable
+   <envar>PGSYSCONFDIR</envar>.
   </para>
 
   <para>
-   The file uses an <quote>INI file</quote> format where the section
+   Either service file uses an <quote>INI file</quote> format where the section
    name is the service name and the parameters are connection
    parameters; see <xref linkend="libpq-paramkeywords"/> for a list.  For
    example:
@@ -8121,9 +8126,22 @@ host=somehost
 port=5433
 user=admin
 </programlisting>
-   An example file is provided at
+   An example file is provided in
+   the <productname>PostgreSQL</productname> installation at
    <filename>share/pg_service.conf.sample</filename>.
   </para>
+
+  <para>
+   Connection parameters obtained from a service file are combined with
+   parameters obtained from other sources.  A service file setting
+   overrides the corresponding environment variable, and in turn can be
+   overridden by a value given directly in the connection string.
+   For example, using the above service file, a connection string
+   <literal>service=mydb port=5434</literal> will use
+   host <literal>somehost</literal>, port <literal>5434</literal>,
+   user <literal>admin</literal>, and other parameters as set by
+   environment variables or built-in defaults.
+  </para>
  </sect1>
 
 

doc/src/sgml/pgbuffercache.sgml

@@ -96,7 +96,7 @@
       </para>
       <para>
        Fork number within the relation;  see
-       <filename>include/common/relpath.h</filename>
+       <filename>common/relpath.h</filename>
       </para></entry>
      </row>