Execution: Add stderr block

Add a stderr block.
Pros:
  - we can make use of dbg macro in our code
Cons:
  - there's a limitation that the compile message also shows

Applies patches from rust-lang/mdBook#1315 since the original change
was not merged by rust-lang.

Signed-off-by: Alx-Lai <[email protected]>

theme/book.js

@@ -110,10 +110,17 @@ function playground_text(playground, hidden = true) {
     }
 
     function run_rust_code(code_block) {
-        var result_block = code_block.querySelector(".result");
+        var result_stderr_block = code_block.querySelector(".result.stderr");
+        if (!result_stderr_block) {
+            result_stderr_block = document.createElement('code');
+            result_stderr_block.className = 'result stderr hljs nohighlight';
+
+            code_block.append(result_stderr_block);
+        }
+        var result_block = code_block.querySelector(".result.stdout");
         if (!result_block) {
             result_block = document.createElement('code');
-            result_block.className = 'result hljs language-bash';
+            result_block.className = 'result stdout hljs nohighlight';
 
             code_block.append(result_block);
         }
@@ -127,10 +134,13 @@ function playground_text(playground, hidden = true) {
             edition = "2021";
         }
         var params = {
-            version: "stable",
-            optimize: "0",
+            backtrace: true,
+            channel: "stable",
             code: text,
-            edition: edition
+            edition: edition,
+            mode: "debug",
+            tests: false,
+            crateType: "bin",
         };
 
         if (text.indexOf("#![feature") !== -1) {
@@ -141,7 +151,7 @@ function playground_text(playground, hidden = true) {
 
         const playgroundModified = isPlaygroundModified(code_block);
         const startTime = window.performance.now();
-        fetch_with_timeout("https://play.rust-lang.org/evaluate.json", {
+        fetch_with_timeout("https://play.rust-lang.org/execute", {
             headers: {
                 'Content-Type': "application/json",
             },
@@ -158,13 +168,15 @@ function playground_text(playground, hidden = true) {
                 "latency": (endTime - startTime) / 1000,
             });
 
-            if (response.result.trim() === '') {
+            if (response.stdout.trim() === '') {
                 result_block.innerText = "No output";
                 result_block.classList.add("result-no-output");
             } else {
-                result_block.innerText = response.result;
+                result_block.innerText = response.stdout;
                 result_block.classList.remove("result-no-output");
             }
+
+            result_stderr_block.innerText = response.stderr;
         })
         .catch(error => {
             const endTime = window.performance.now();