docs: Add a missing comma in Rust debugging JSON (#36007)

Matt created 

Update the Rust debugging doc to include a missing comma in one of the
example JSON's.

Change summary

docs/src/languages/rust.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Detailed changes

docs/src/languages/rust.md 🔗 

@@ -326,7 +326,7 @@ When you use `cargo build` or `cargo test` as the build command, Zed can infer t
 [
   {
     "label": "Build & Debug native binary",
-    "adapter": "CodeLLDB"
+    "adapter": "CodeLLDB",
     "build": {
       "command": "cargo",
       "args": ["build"]