fix: correct typos and improve code clarity (#14341)

- Fix 'clipbard' typos in clipboard.rs (function names, comments, strings)
- Fix 'seperate' typo in x11/server.rs comment
- Replace !is_ok() with idiomatic is_err() in updater.rs
- Fix double backtick typo in updater.rs comment

Co-authored-by: Ocean <ocean@Mac-mini-von-Ocean.local>

src/updater.rs

@@ -123,7 +123,7 @@ fn check_update(manually: bool) -> ResultType<()> {
     if !(manually || config::Config::get_bool_option(config::keys::OPTION_ALLOW_AUTO_UPDATE)) {
         return Ok(());
     }
-    if !do_check_software_update().is_ok() {
+    if do_check_software_update().is_err() {
         // ignore
         return Ok(());
     }
@@ -185,7 +185,7 @@ fn check_update(manually: bool) -> ResultType<()> {
             let mut file = std::fs::File::create(&file_path)?;
             file.write_all(&file_data)?;
         }
-        // We have checked if the `conns`` is empty before, but we need to check again.
+        // We have checked if the `conns` is empty before, but we need to check again.
         // No need to care about the downloaded file here, because it's rare case that the `conns` are empty
         // before the download, but not empty after the download.
         if has_no_active_conns() {