Rollup merge of #41173 - GuillaumeGomez:fix-rustdoc-code-block-parsing, r=steveklabnik

Fix block code headers parsing

Fixes #41167.

r? @rust-lang/docs

Author: frewsxcv

src/librustdoc/html/markdown.rs

@@ -469,22 +469,28 @@ impl LangString {
         );
 
         for token in tokens {
-            match token {
+            match token.trim() {
                 "" => {},
-                "should_panic" => { data.should_panic = true; seen_rust_tags = true; },
-                "no_run" => { data.no_run = true; seen_rust_tags = true; },
-                "ignore" => { data.ignore = true; seen_rust_tags = true; },
-                "rust" => { data.rust = true; seen_rust_tags = true; },
-                "test_harness" => { data.test_harness = true; seen_rust_tags = true; },
+                "should_panic" => {
+                    data.should_panic = true;
+                    seen_rust_tags = seen_other_tags == false;
+                }
+                "no_run" => { data.no_run = true; seen_rust_tags = !seen_other_tags; }
+                "ignore" => { data.ignore = true; seen_rust_tags = !seen_other_tags; }
+                "rust" => { data.rust = true; seen_rust_tags = true; }
+                "test_harness" => {
+                    data.test_harness = true;
+                    seen_rust_tags = !seen_other_tags || seen_rust_tags;
+                }
                 "compile_fail" if allow_compile_fail => {
                     data.compile_fail = true;
-                    seen_rust_tags = true;
+                    seen_rust_tags = !seen_other_tags || seen_rust_tags;
                     data.no_run = true;
                 }
                 x if allow_error_code_check && x.starts_with("E") && x.len() == 5 => {
                     if let Ok(_) = x[1..].parse::<u32>() {
                         data.error_codes.push(x.to_owned());
-                        seen_rust_tags = true;
+                        seen_rust_tags = !seen_other_tags || seen_rust_tags;
                     } else {
                         seen_other_tags = true;
                     }
@@ -670,9 +676,11 @@ mod tests {
         t("test_harness",          false,        false,  false,  true,  true,  false, Vec::new());
         t("compile_fail",          false,        true,   false,  true,  false, true,  Vec::new());
         t("{.no_run .example}",    false,        true,   false,  true,  false, false, Vec::new());
-        t("{.sh .should_panic}",   true,         false,  false,  true,  false, false, Vec::new());
+        t("{.sh .should_panic}",   true,         false,  false,  false, false, false, Vec::new());
         t("{.example .rust}",      false,        false,  false,  true,  false, false, Vec::new());
         t("{.test_harness .rust}", false,        false,  false,  true,  true,  false, Vec::new());
+        t("text, no_run",          false,        true,   false,  false, false, false, Vec::new());
+        t("text,no_run",           false,        true,   false,  false, false, false, Vec::new());
     }
 
     #[test]