RecursionError: maximum recursion depth exceeded while calling a Python object

Hi,

When I run FORD I get the following error. I made no change on source codes or FORD project file after I had ran without problem a while ago, probably before upgrading the installed version.

```Correlating information from different parts of your project...

Traceback (most recent call last):
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 196, in _run_module_as_main
return _run_code(code, main_globals, None,
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\runpy.py", line 86, in _run_code
exec(code, run_globals)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\Scripts\ford.exe\__main__.py", line 7, in
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\__init__.py", line 647, in run
main(proj_data, proj_docs, md)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\__init__.py", line 596, in main
project.make_links(base_url)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\fortran_project.py", line 326, in make_links
src.make_links(self)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\sourceform.py", line 461, in make_links
item.make_links(project)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\sourceform.py", line 461, in make_links
item.make_links(project)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\sourceform.py", line 461, in make_links
item.make_links(project)
[Previous line repeated 988 more times]
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\sourceform.py", line 454, in make_links
self.doc = ford.utils.sub_links(self.doc, project)
File "C:\Users\tuncaen\AppData\Local\Programs\Python\Python310\lib\site-packages\ford\utils.py", line 322, in sub_links
string = LINK_RE.sub(convert_link, string)
RecursionError: maximum recursion depth exceeded while calling a Python object
```

The project file:

```
project: UIHES_v1.00
src_dir: ../src/
page_dir:../md
md_extensions: markdown.extensions.toc
md_base_dir: ../src_comment/
output_dir: ../doc/
media_dir: ../ford-data/
sort: src
author: Enes Tunca
author_description: PhD Candidate @ITU Naval Architecture
github: https://github.com/tuncaen
email: mailto:tuncaenes@gmail.com
docmark: <
predocmark: >
predocmark_alt: #
display: public
protected
private
source: true
graph: true
search: true
parallel: 4
warn: true
preprocess: false
```