Make markdownlint happier

PLUGINS.md

@@ -144,6 +144,7 @@ the `enable` and `disable` functions and any plugin hooks registered in `enable`
 
 
 ### Manifest format
+
 The plugin's package directory MUST contain a file `MANIFEST.toml`.
 
 > ***Discussion:** Is TOML the proper format, or should something like JSON or YAML be preferred?*
@@ -421,7 +422,7 @@ Which additional extension points should be supported?
 ### Support for ZIP compressed plugins:
 
 As before plugins in a single ZIP archive could also be supported. The "Format"
-section above could be extended with:
+section above could be extended with following paragraph.
 
 > The plugin package MAY be put into a ZIP archive. In this case the filename
 > must be the same as the plugin package name followed by `.picard.zip`, e.g.