Fix issue with code after headings without whitespace

Fixes "Invalid face reference: markdown-header-face-7" error.

Closes GH-234.

markdown-mode.el

@@ -7170,7 +7170,9 @@ Calls `markdown-cycle' with argument t."
 (defun markdown-outline-level ()
   "Return the depth to which a statement is nested in the outline."
   (cond
-   ((markdown-code-block-at-point-p) 7) ;; Only 6 header levels are defined.
+   ((and (match-beginning 0)
+         (markdown-code-block-at-pos (match-beginning 0)))
+    7) ;; Only 6 header levels are defined.
    ((match-end 2) 1)
    ((match-end 3) 2)
    ((match-end 4)

tests/markdown-test.el

@@ -2940,6 +2940,25 @@ takes precedence)."
     (should (markdown-on-heading-p))
     (should-not (markdown-range-property-any 453 484 'face '(markdown-hr-face)))))
 
+(ert-deftest test-markdown-font-lock/heading-code-block-no-whitespace ()
+  "Headings immediately before code blocks should be identified correctly.
+See GH-234."
+  (markdown-test-string
+   "#### code snippet
+```javascript
+const styles = require('gadgets/dist/styles.css');
+```"
+   (goto-char (point-min))
+   (forward-word)
+   (should (markdown-on-heading-p))
+   (should (markdown-match-propertized-text 'markdown-heading (point-at-eol)))
+   (goto-char (match-beginning 0))
+   (should (markdown-outline-level))
+   (should (= (markdown-outline-level) 4))
+   (markdown-test-range-has-face 6 17 'markdown-header-face-4)
+   (end-of-line)
+   (should-not (markdown-code-block-at-point-p))))
+
 (ert-deftest test-markdown-font-lock/inline-attributes ()
   "Test inline attributes before a fenced code block."
   (markdown-test-file "Leanpub.md"