Only leave space for git diff markers if any line is modified (#3406)

Previously, setting `--style=changes` would always print a 2-space
indent, even if the file was unmodified. This changes the style to only
print an indent if there is at least one +/- git marker in the sidebar.

src/printer.rs

@@ -227,7 +227,9 @@ impl<'a> InteractivePrinter<'a> {
 
         #[cfg(feature = "git")]
         {
-            if config.style_components.changes() {
+            if config.style_components.changes()
+                && line_changes.as_ref().is_some_and(|c| !c.is_empty())
+            {
                 decorations.push(Box::new(LineChangesDecoration::new(&colors)));
             }
         }