replace spaces by dashes

src/utils/markdown.rs

@@ -61,7 +61,13 @@ pub fn get_options(path: Option<FilePath>, metadata_type: MType) -> ComrakOption
             .superscript(true)
             .header_ids(match path {
                 Some(ref fp) => {
-                    format!("{}-", fp.path.get(..fp.path.len() - 3).unwrap_or_default())
+                    format!(
+                        "{}-",
+                        fp.path
+                            .get(..fp.path.len() - 3)
+                            .unwrap_or_default()
+                            .replace(' ', "-")
+                    )
                 }
                 None => String::new(),
             })