fix(deep-link): duplicate MimeType entries added to .desktop

just check that it isn't already in there before appending it

.changes/deep-link-xdg-mime-fix.md

@@ -4,3 +4,4 @@
 ---
 
 Fix deep link protocol handler not set as default on linux
+Fix duplicate protocols added to MimeType section in .desktop files on linux

plugins/deep-link/src/lib.rs

@@ -303,13 +303,16 @@ mod imp {
 
                 if let Ok(mut desktop_file) = ini::Ini::load_from_file(&target_file) {
                     if let Some(section) = desktop_file.section_mut(Some("Desktop Entry")) {
-                        let old_mimes = section.remove("MimeType");
-                        section.append(
-                            "MimeType",
-                            format!("{mime_type};{}", old_mimes.unwrap_or_default()),
-                        );
+                        // it's ok to remove it - we only write to the file if it's missing
+                        // and in that case we include old_mimes
+                        let old_mimes = section.remove("MimeType").unwrap_or_default();
+
+                        if !old_mimes.split(';').any(|mime| mime == mime_type) {
+                            section.remove("MimeType");
+                            section.append("MimeType", format!("{mime_type};{}", old_mimes));
                             desktop_file.write_to_file(&target_file)?;
                         }
+                    }
                 } else {
                     let mut file = File::create(target_file)?;
                     file.write_all(