Ghostty supports OSC 9;4 (#2724)

This enables the new in-terminal progress bar (which uses OSC 9;4) if
nextest is running inside the Ghostty terminal.

See #2715

Here's a video of it working, with my local nextest build.


https://github.com/user-attachments/assets/bd5c7918-7335-45c9-95a2-21108ece2493

It also does a tiny incidental refactor, making the other
terminal-specific checks use `var_os` instead of `var` to use fewer
allocations.

---------

Co-authored-by: RGBCube <git@rgbcu.be>

Author: adamchalmers

nextest-runner/src/reporter/displayer/progress.rs

@@ -598,18 +598,22 @@ fn supports_osc_9_4(stream: &dyn IsTerminal) -> bool {
         );
         return false;
     }
-    if std::env::var("WT_SESSION").is_ok() {
+    if std::env::var_os("WT_SESSION").is_some() {
         debug!("autodetect terminal progress reporting: enabling since WT_SESSION is set");
         return true;
     };
-    if std::env::var("ConEmuANSI").ok() == Some("ON".into()) {
+    if std::env::var_os("ConEmuANSI").is_some_and(|term| term == "ON") {
         debug!("autodetect terminal progress reporting: enabling since ConEmuANSI is ON");
         return true;
     }
-    if std::env::var("TERM_PROGRAM").ok() == Some("WezTerm".into()) {
+    if std::env::var_os("TERM_PROGRAM").is_some_and(|term| term == "WezTerm") {
         debug!("autodetect terminal progress reporting: enabling since TERM_PROGRAM is WezTerm");
         return true;
     }
+    if std::env::var_os("TERM_PROGRAM").is_some_and(|term| term == "ghostty") {
+        debug!("autodetect terminal progress reporting: enabling since TERM_PROGRAM is Ghostty");
+        return true;
+    }
 
     false
 }