Use "Pg" instead of "PG" in new PgError related identifiers

Arguably, PGError might have been better. But since the precedent is
long since established it is better to be consistent.

pgconn/config.go

@@ -60,10 +60,10 @@ type Config struct {
 	// OnNotification is a callback function called when a notification from the LISTEN/NOTIFY system is received.
 	OnNotification NotificationHandler
 
-	// OnPGError is a callback function called when a Postgres error is received by the server. The default handler will close
+	// OnPgError is a callback function called when a Postgres error is received by the server. The default handler will close
 	// the connection on any FATAL errors. If you override this handler you should call the previously set handler or ensure
 	// that you close on FATAL errors by returning false.
-	OnPGError ErrorPGHandler
+	OnPgError PgErrorHandler
 
 	createdByParseConfig bool // Used to enforce created by ParseConfig rule.
 }
@@ -266,7 +266,7 @@ func ParseConfigWithOptions(connString string, options ParseConfigOptions) (*Con
 		BuildFrontend: func(r io.Reader, w io.Writer) *pgproto3.Frontend {
 			return pgproto3.NewFrontend(r, w)
 		},
-		OnPGError: func(_ *PgConn, pgErr *PgError) bool {
+		OnPgError: func(_ *PgConn, pgErr *PgError) bool {
 			// we want to automatically close any fatal errors
 			if strings.EqualFold(pgErr.Severity, "FATAL") {
 				return false

pgconn/pgconn.go

@@ -52,11 +52,11 @@ type LookupFunc func(ctx context.Context, host string) (addrs []string, err erro
 // BuildFrontendFunc is a function that can be used to create Frontend implementation for connection.
 type BuildFrontendFunc func(r io.Reader, w io.Writer) *pgproto3.Frontend
 
-// ErrorPGHandler is a function that handles errors returned from Postgres. This function must return true to keep
+// PgErrorHandler is a function that handles errors returned from Postgres. This function must return true to keep
 // the connection open. Returning false will cause the connection to be closed immediately. You should return
 // false on any FATAL-severity errors. This will not receive network errors. The *PgConn is provided so the handler is
 // aware of the origin of the error, but it must not invoke any query method.
-type ErrorPGHandler func(*PgConn, *PgError) bool
+type PgErrorHandler func(*PgConn, *PgError) bool
 
 // NoticeHandler is a function that can handle notices received from the PostgreSQL server. Notices can be received at
 // any time, usually during handling of a query response. The *PgConn is provided so the handler is aware of the origin
@@ -554,7 +554,7 @@ func (pgConn *PgConn) receiveMessage() (pgproto3.BackendMessage, error) {
 		pgConn.parameterStatuses[msg.Name] = msg.Value
 	case *pgproto3.ErrorResponse:
 		err := ErrorResponseToPgError(msg)
-		if pgConn.config.OnPGError != nil && !pgConn.config.OnPGError(pgConn, err) {
+		if pgConn.config.OnPgError != nil && !pgConn.config.OnPgError(pgConn, err) {
 			pgConn.status = connStatusClosed
 			pgConn.conn.Close() // Ignore error as the connection is already broken and there is already an error to return.
 			close(pgConn.cleanupDone)

pgconn/pgconn_test.go

@@ -3148,7 +3148,7 @@ func TestPipelineCloseDetectsUnsyncedRequests(t *testing.T) {
 	require.EqualError(t, err, "pipeline has unsynced requests")
 }
 
-func TestConnOnPGError(t *testing.T) {
+func TestConnOnPgError(t *testing.T) {
 	t.Parallel()
 
 	ctx, cancel := context.WithTimeout(context.Background(), 120*time.Second)
@@ -3156,7 +3156,7 @@ func TestConnOnPGError(t *testing.T) {
 
 	config, err := pgconn.ParseConfig(os.Getenv("PGX_TEST_DATABASE"))
 	require.NoError(t, err)
-	config.OnPGError = func(c *pgconn.PgConn, pgErr *pgconn.PgError) bool {
+	config.OnPgError = func(c *pgconn.PgConn, pgErr *pgconn.PgError) bool {
 		require.NotNil(t, c)
 		require.NotNil(t, pgErr)
 		// close connection on undefined tables only