Fix YAML print idempotency for asterisk placeholders inside block scalars (#7466)

The asterisk placeholder preprocessing (introduced in #6626 to handle
credential values like `*** REMOVED ***`) replaces matched text with
UUIDs before parsing and restores them afterward. Restoration for the
variable/asterisk UUID map used exact-match against the scalar value,
so when the regex matched inside a multi-line block scalar — e.g.
markdown bold like `**CI Alert**` on a line containing `: ` from an
emoji — the UUID was embedded within a longer scalar value and never
restored, breaking print idempotency.

Align restoration with the helm and single-brace template maps on the
same code path, which already use `contains`/`replace`. UUIDs are
random per-parse and only produced by the parser, so substring
replacement is unambiguous.

Author: knutwannheden

rewrite-yaml/src/main/java/org/openrewrite/yaml/YamlParser.java

@@ -345,9 +345,14 @@ private Yaml.Documents parseFromInput(Path sourceFile, EncodingDetectingInputStr
                                 scalarValue = scalarValue.replace(entry.getKey(), entry.getValue());
                             }
                         }
-                        // Then check for variable UUIDs (these are exact matches)
-                        if (variableByUuid.containsKey(scalarValue)) {
-                            scalarValue = variableByUuid.get(scalarValue);
+                        // Then restore any variable/asterisk placeholder UUIDs. The UUID may be
+                        // the entire scalar value (e.g. `key: @var@`) or embedded within a longer
+                        // scalar (e.g. markdown bold text inside a block scalar that happened to
+                        // match the asterisk placeholder regex).
+                        for (Map.Entry<String, String> entry : variableByUuid.entrySet()) {
+                            if (scalarValue.contains(entry.getKey())) {
+                                scalarValue = scalarValue.replace(entry.getKey(), entry.getValue());
+                            }
                         }
 
                         Yaml.Scalar.Style style;

rewrite-yaml/src/test/java/org/openrewrite/yaml/YamlParserTest.java

@@ -266,6 +266,25 @@ void asteriskPlaceholdersWithAnchors() {
         );
     }
 
+    @Test
+    void asteriskPatternInsideBlockScalar() {
+        // Markdown bold text inside a literal block scalar must not be mangled
+        // by the asterisk placeholder preprocessing.
+        rewriteRun(
+          yaml(
+            """
+              jobs:
+                alert:
+                  steps:
+                    - name: Post alert
+                      run: |
+                        echo ":rotating_light: **CI Alert**: repo has been failing for **5 days**"
+                        echo "- **Branch:** main"
+              """
+          )
+        );
+    }
+
     @Test
     void pipeLiteralInASequenceWithDoubleQuotes() {
         rewriteRun(