do a better job of printing integral floats.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "scryer-prolog"
-version = "0.8.14"
+version = "0.8.15"
 authors = ["Mark Thom <markjordanthom@gmail.com>"]
 repository = "https://github.com/mthom/scryer-prolog"
 description = "A modern Prolog implementation written mostly in Rust."

src/prolog/heap_print.rs

@@ -507,11 +507,12 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter>
                         self.append_str("0");
                     });
                 } else {
-                    let output_str = format!("{}", fl);
+                    let OrderedFloat(fl) = fl;
+                    let output_str = format!("{0:<20?}", fl);
 
                     push_space_if_amb!(self, &output_str, {
-                        self.append_str(&output_str);
-                    });
+                        self.append_str(&output_str.trim());
+                    });                
                 },
             Constant::Number(n) => {
                 let output_str = format!("{}", n);