Fix remaining wsl_v5 whitespace findings (refs #61)

Insert the blank line wsl_v5 requires above `defer` and `go`
statements that share no variables with the statement above them.
Applied mechanically via `make lint-fix`; the diff is 60 added blank
lines and nothing else.

internal/chunker/chunker.go

@@ -163,6 +163,7 @@ func (c *Chunker) ChunkFile(path string) ([]Chunk, error) {
 	if err != nil {
 		return nil, fmt.Errorf("opening file: %w", err)
 	}
+
 	defer func() {
 		err := file.Close()
 		if err != nil && err.Error() != "invalid argument" {