Fix name in categories directive

The name can contain backslashes that need converting to
posix format before going into the subsequent code. Otherwise
the backslashes will break the documentation folder structure.

docs/sphinxext/mantiddoc/directives/categories.py

@@ -129,7 +129,10 @@ def __init__(self, name, docname, src_path):
         self.section = docname.parts[0]
         dirpath = docname.parent
         html_dir = dirpath.joinpath(CATEGORIES_DIR)
-        self.html_path = html_dir.joinpath(name + ".html")
+        # name can arrive with a format like "MyAlgorithmCategory\\NameOfAlgorithm", so we
+        # have to sort those slashes out
+        name_with_slashes_fixed = name.replace("\\", "/").replace("//", "/")
+        self.html_path = html_dir.joinpath(name_with_slashes_fixed + ".html")
         super(Category, self).__init__(name, self.html_path)
         self.pages = set([])
         self.subcategories = set([])
@@ -446,7 +449,7 @@ def create_top_algorithm_category(categories):
     top_context["facilitycategories"] = sorted(facility_categories, key=lambda x: x.name)
     top_context["title"] = "Algorithm Contents"
     top_html_path_noext = str(Path("algorithms", "index"))
-    return (str(top_html_path_noext), top_context, template)
+    return (top_html_path_noext, top_context, template)
 
 
 def extract_matching_categories(input_categories, filepath):