Merge branch '529-feature-request-syntax-highlighting-of-code-blocks'…

… into 'main'

Resolve "Feature Request: syntax highlighting of code blocks"

Closes #529

See merge request pub/terrareg!408

docs/modules/best_practices.md

@@ -6,6 +6,42 @@ Terrareg has been extensively tested with Terraform modules of all shapes and si
 
 However, to get the _most_ out of Terrareg, there are some practices/guides that will help.
 
+## Markdown
+
+Markdown files can be indexed and shown as tabs.
+
+The README.md in a root module, sub-modules and examples are indexed by default.
+
+Additional markdown files can be indexed and shown as tabs using [ADDITIONAL_MODULE_TABS](../CONFIG.md#additional_module_tabs)
+
+Code blocks are shown with syntax highlighting, with the following supported languages:
+
+ * `hcl`
+ * `css`
+ * `bash`
+ * `batch`
+ * `docker`
+ * `hcl`
+ * `plsql`
+ * `powershell`
+ * `python`
+ * `sql`
+
+Auto-detection of languages is used, but it's safest to write with language-helper markup, e.g.:
+````
+```hcl
+terraform {
+  required_version = "0.1.2
+}
+```
+
+```bash
+#!/bin/bash
+
+echo Some bash script
+```
+````
+
 ## Terrareg metadata file
 
 A metadata file can be provided each an uploaded module's archive to provide additional metadata to terrareg.

terrareg/utils.py

@@ -118,8 +118,10 @@ def sanitise_html_content(text, allow_markdown_html=False):
             # Custom allowed attributes
             'h1': ['id'], 'h2': ['id'], 'h3': ['id'],
             'h4': ['id'], 'h5': ['id'], 'h6': ['id'],
-            'img': ['src']
+            'img': ['src'],
+            'code': ['class']
         }
+
     return (
         bleach.clean(
             text, **kwargs