output: get rid of an unsafe block (#1636)

* parse: fix build in debug mode

This fixes a build failure in debug mode, as the value to be printed
does not implement Display.

* output: get rid of an unsafe block

This get rid of an unsafe block which is not necessary, and only used
when building in debug mode.

src/output/help.rs

@@ -998,14 +998,10 @@ impl<'b, 'c, 'd, 'w> Help<'b, 'c, 'd, 'w> {
                 _ => continue,
             };
 
-            debugln!("Help::write_template_help:iter: tag_buf={};", unsafe {
-                String::from_utf8_unchecked(
-                    tag_buf.get_ref()[0..tag_length]
-                        .iter()
-                        .map(|&i| i)
-                        .collect::<Vec<_>>(),
-                )
-            });
+            debugln!(
+                "Help::write_template_help:iter: tag_buf={};",
+                String::from_utf8_lossy(&tag_buf.get_ref()[0..tag_length])
+            );
             match &tag_buf.get_ref()[0..tag_length] {
                 b"?" => {
                     self.writer.write_all(b"Could not decode tag name")?;

src/parse/validator.rs

@@ -279,7 +279,7 @@ impl<'b, 'c, 'z> Validator<'b, 'c, 'z> {
                         self.p.app.color(),
                     ));
                     debugln!(
-                        "Validator::validate_conflicts_with_everything; ERROR: {}",
+                        "Validator::validate_conflicts_with_everything; ERROR: {:?}",
                         err
                     );
                     return err;