Add code issue template and link Contribute button to it

- Create .github/ISSUE_TEMPLATE/code-issue.yml for reporting code bugs in patterns
- Update generate.java to use the new template with pre-filled category and slug

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: brunoborges

.github/ISSUE_TEMPLATE/code-issue.yml

@@ -0,0 +1,88 @@
+---
+name: Code Issue in Pattern
+description: Report incorrect, outdated, or broken code in an existing pattern
+title: "[Code Issue] "
+labels: ["bug", "slug"]
+body:
+  - type: markdown
+    attributes:
+      value: |
+        ## Report a code issue
+
+        Found a bug, compilation error, or inaccuracy in the code examples
+        of an existing pattern? Let us know so we can fix it.
+
+  - type: dropdown
+    id: category
+    attributes:
+      label: Category
+      options:
+        - language
+        - collections
+        - strings
+        - streams
+        - concurrency
+        - io
+        - errors
+        - datetime
+        - security
+        - tooling
+        - enterprise
+    validations:
+      required: true
+
+  - type: input
+    id: slug
+    attributes:
+      label: Pattern slug
+      description: "The slug of the affected pattern (e.g., `type-inference-with-var`)"
+      placeholder: "type-inference-with-var"
+    validations:
+      required: true
+
+  - type: dropdown
+    id: affected-code
+    attributes:
+      label: Which code is affected?
+      options:
+        - Old code example
+        - Modern code example
+        - Both
+    validations:
+      required: true
+
+  - type: dropdown
+    id: issue-type
+    attributes:
+      label: Type of issue
+      options:
+        - Code doesn't compile
+        - Incorrect or misleading output
+        - Outdated API usage
+        - Missing imports or context
+        - Better modern alternative exists
+        - Other
+    validations:
+      required: true
+
+  - type: textarea
+    id: description
+    attributes:
+      label: Describe the issue
+      description: "Explain what's wrong with the current code"
+    validations:
+      required: true
+
+  - type: textarea
+    id: suggested-fix
+    attributes:
+      label: Suggested fix
+      description: "If you have a fix, paste the corrected code here"
+      render: java
+
+  - type: input
+    id: jdk-version
+    attributes:
+      label: JDK version tested
+      description: "Which JDK version did you use to identify this issue?"
+      placeholder: "21"

html-generators/generate.java

@@ -419,13 +419,11 @@ String renderSocialShare(String tpl, String slug, String title, Map<String, Stri
 static final String GITHUB_ISSUES_URL = "https://github.com/javaevolved/javaevolved.github.io/issues/new";
 
 Map<String, String> buildContributeUrls(Snippet s, String locale, String localeName) {
-    var pageUrl = locale.equals("en")
-            ? "%s/%s/%s.html".formatted(BASE_URL, s.category(), s.slug())
-            : "%s/%s/%s/%s.html".formatted(BASE_URL, locale, s.category(), s.slug());
-
-    var codeTitle = urlEncode("[Code Issue] %s".formatted(s.title()));
-    var codeBody = urlEncode("**Pattern:** %s\n**URL:** %s\n\nDescribe the issue:\n".formatted(s.slug(), pageUrl));
-    var codeUrl = "%s?title=%s&labels=%s&body=%s".formatted(GITHUB_ISSUES_URL, codeTitle, "bug", codeBody);
+    var codeUrl = "%s?template=code-issue.yml&title=%s&category=%s&slug=%s".formatted(
+            GITHUB_ISSUES_URL,
+            urlEncode("[Code Issue] %s".formatted(s.title())),
+            urlEncode(s.category()),
+            urlEncode(s.slug()));
 
     var cleanLocaleName = localeName.replaceFirst("^[^\\p{L}]+", "");
     var transUrl = "%s?template=translation-issue.yml&title=%s&locale=%s&pattern=%s&area=%s".formatted(