docs: Get mkdocs working

docs/extra.css

@@ -0,0 +1,3 @@
+ins {
+	text-decoration: underline;
+}

mkdocs.yml

@@ -7,15 +7,17 @@ nav:
 plugins:
 - search
 - semiliterate:
-    ignore_folders: [target]
+    ignore_folders: [target, lib]
     exclude_extensions: ['.o', '.hi']
     extract_standard_markdown:
       terminate: <!-- /md -->
 theme:
   name: readthedocs
+  prev_next_buttons_location: both
+extra_css: [extra.css]
 markdown_extensions:
 - attr_list
-- markdown-del-ins
+- markdown_del_ins
 - pymdownx.superfences
 - pymdownx.highlight:
     use_pygments: true

tests/basic.spt

@@ -35,14 +35,14 @@ cloning this fostr project. Then, either:
    
 For example, this snippet generates the following Python:
 ```python
-{! ../examples/emit_sum.py extract:
+{! ../tests/emit_sum.py extract:
   start: 'Stdio\s='
 !}
 ```
 (which writes "192" to standard output), or this non-idiomatic, inefficient, but
 working Javascript:
 ```javascript
-{! ../examples/emit_sum.js extract:
+{! ../tests/emit_sum.js extract:
   start: '^}'
 !}
 ```