docs: make mkdocs_hooks.transform more robust

- Keeps the markdown inside the code blocks as is
- Logs the modified lines (mkdocs serve —verbose)

Signed-off-by: Damien Martin <damlobster@gmail.com>

docs/_klipper3d/mkdocs_hooks.py

@@ -1,18 +1,31 @@
 import re
+import logging
+
+logger = logging.getLogger('mkdocs.mkdocs_hooks.transform')
 
 def transform(markdown: str, page, config, files):
+    in_code_block = 0
     in_list = False
     lines = markdown.splitlines()
     for i in range(len(lines)):
-        lines[i] = lines[i].replace('](../',
-                                    f"]({config['repo_url']}blob/master/")
-        lines[i] = re.sub(r"\\", "<br>", lines[i])
-        # check that lists at level 0 are not indented (no space before *|-|1.)
-        if len(lines[i]) == 0:
-            in_list = False
-        elif re.match(r"^(\*|-|\d+\.) ", lines[i]):
-            in_list = True
-        if not in_list:
-            lines[i] = re.sub(r"^\s+(\*|-|\d+\.) ", r"\1 ", lines[i])
+        line_out = lines[i]
+        in_code_block = (in_code_block +
+            len(re.findall("\s*[`]{3,}", line_out))) % 2
+        if not in_code_block:
+            line_out = line_out.replace('](../',
+                                        f"]({config['repo_url']}blob/master/")
+            line_out = re.sub("\\\s*$", "<br>", line_out)
+            # check that lists at level 0 are not indented
+            # (no space before *|-|1.)
+            if len(line_out) == 0:
+                in_list = False
+            elif re.match(r"^(\*|-|\d+\.) ", line_out):
+                in_list = True
+            if not in_list:
+                line_out = re.sub(r"^\s+(\*|-|\d+\.) ", r"\1 ", line_out)
+            if line_out != lines[i]:
+                logger.debug((f'[mkdocs_hooks] rewrite line {i+1}: '
+                        f'"{lines[i]}" -> "{line_out}"'))
+            lines[i] = line_out
     output = "\n".join(lines)
     return output