tweaks

Author: willmcgugan

docs/api/constants.md

@@ -2,5 +2,4 @@
 title: "textual.constants"
 ---
 
-
 ::: textual.constants

docs/api/signal.md

@@ -2,5 +2,4 @@
 title: "textual.signal"
 ---
 
-
 ::: textual.signal

mkdocs-common.yml

@@ -78,6 +78,8 @@ plugins:
           separate_signature: true
           signature_crossrefs: true
           merge_init_into_class: true
+          parameter_headings: true
+          show_root_heading: false
           docstring_options:
             ignore_init_summary: true
           show_source: false