chore: Satisfy flake8

mkdocs_semiliterate/plugin.py

@@ -20,7 +20,7 @@ import yaml
 
 
 class StreamInclusion(StreamExtract):
-    """ md  An extension of the StreamExtract class which adds
+    r""" md  An extension of the StreamExtract class which adds
 
 ### Inclusion syntax
 
@@ -36,7 +36,8 @@ enclosed in single or double quotes. Note that FILENAME is interpreted relative
 to the directory in which the file containing the `{! .. !}` expression
 resides. The YAML is interpreted exactly as the extraction options to a
 `semiliterate` item as
-[documented](https://athackst.github.io/mkdocs-simple-plugin/mkdocs_simple_plugin/plugin/index.html#semiliterate)
+[documented](https://athackst.github.io/mkdocs-simple-plugin/
+mkdocs_simple_plugin/plugin/index.html#semiliterate)
 for the `simple` extension. The text extracted from FILENAME
 is interpolated at the current location in the file currently being written.
 Recursive inclusion is supported.
@@ -61,7 +62,8 @@ to take advantage of the beginning of the `setup.cfg` file:
 
 (and of course both of the code snippets just above are extracted into this
 page with `{! ... !}`, as you can see in the
-[source code](https://code.studioinfinity.org/glen/mkdocs-semiliterate/src/branch/main/mkdocs_semiliterate/plugin.py)
+[source code](https://code.studioinfinity.org/glen/mkdocs-semiliterate/src/
+branch/main/mkdocs_semiliterate/plugin.py)
 for the plugin.)
 
 Note that a `{! ... !}` directive must be in a line that semiliterate would