Add examples of headings shared by pages with wrong IDs

Author: romaricpascal

example/source/shared-subheadings/page-a.html.md

@@ -0,0 +1,14 @@
+---
+layout: layout
+---
+
+# Shared subheadings - Page A
+
+A page that shares headings with the other pages in this folder,
+to check that the heading IDs are computed properly
+
+## A subheading
+
+### A h3 subheading
+
+## Another subheading

example/source/shared-subheadings/page-b.html.md

@@ -0,0 +1,14 @@
+---
+layout: layout
+---
+
+# Shared subheadings - Page B
+
+A page that shares headings with the other pages in this folder,
+to check that the heading IDs are computed properly
+
+## A subheading
+
+### A h3 subheading
+
+## Another subheading