Add debug only guard for the --wait-dbg flag

crates/rust-analyzer/src/bin/args.rs

@@ -52,7 +52,8 @@ FLAGS:
     --log-file <PATH> Log to the specified file instead of stderr
     --no-buffering    Flush log records to the file immediately
 
-    --wait-dbg        Wait until a debugger is attached to
+    --wait-dbg        Wait until a debugger is attached to.
+                      The flag is valid for debug builds only
 
 ENVIRONMENTAL VARIABLES:
     RA_LOG            Set log filter in env_logger format

crates/rust-analyzer/src/bin/main.rs

@@ -29,6 +29,8 @@ fn main() {
 
 fn try_main() -> Result<()> {
     let args = args::Args::parse()?;
+    
+    #[cfg(debug_assertions)]
     if args.wait_dbg || env::var("RA_WAIT_DBG").is_ok() {
         #[allow(unused_mut)]
         let mut d = 4;