printer CHANGE move ly_out_flush() into public API
Since the API provides generic printer functions and the ouput can be
hidden behinf filepath, the caller may need to flush the output
manually.
diff --git a/src/printer.h b/src/printer.h
index 2614bad..f50a7a1 100644
--- a/src/printer.h
+++ b/src/printer.h
@@ -188,6 +188,12 @@
ssize_t ly_print(struct ly_out *out, const char *format, ...);
/**
+ * @brief Flush the output from any internal buffers and clean any auxiliary data.
+ * @param[in] out Output specification.
+ */
+void ly_print_flush(struct ly_out *out);
+
+/**
* @brief Generic printer of the given string buffer into the specified output.
*
* Alternatively, ly_print() can be used.