Restructure log_line_prefix options to be clearer:

	#log_line_prefix = ''   # %u = user name
                                # %d = database name
                                # %r = remote host and port
                                # %h = remote host
                                # %p = PID
                                # %t = timestamp
                                # %m = timestamp with milliseconds
                                # %i = command tag
                                # %c = session id
                                # %l = session line number
                                # %s = session start timestamp
                                # %x = transaction id
                                # %q = stop here in non-session processes
                                # %% = '%'
                                # e.g. '<%u%%%d> '

src/backend/utils/misc/postgresql.conf.sample

@@ -239,15 +239,21 @@
 #log_connections = false
 #log_disconnections = false
 #log_duration = false
-#log_line_prefix = ''		# e.g. '<%u%%%d> ' 
-				# %u=user name %d=database name
-				# %r=remote host and port %h=remote host
-				# %p=PID %t=timestamp %i=command tag
-				# %m=timestamp with milliseconds
-				# %c=session id %l=session line number
-				# %s=session start timestamp %x=transaction id
-				# %q=stop here in non-session processes
-				# %%='%'
+#log_line_prefix = ''		# %u = user name
+				# %d = database name
+				# %r = remote host and port
+				# %h = remote host
+				# %p = PID
+				# %t = timestamp 
+				# %m = timestamp with milliseconds
+				# %i = command tag
+				# %c = session id
+				# %l = session line number
+				# %s = session start timestamp
+				# %x = transaction id
+				# %q = stop here in non-session processes
+				# %% = '%'
+				# e.g. '<%u%%%d> '
 #log_statement = 'none'		# none, mod, ddl, all
 #log_hostname = false