Delete trailing whitespace for yaml files

.github/workflows/docs.yml

@@ -3,7 +3,7 @@ name: Publish docs
 on:
   push:
     branches:
-      - master 
+      - master
 permissions:
   contents: write
 jobs:

mkdocs.yml

@@ -7,7 +7,7 @@ theme:
     - scheme: default
       primary: black
       toggle:
-        icon: material/brightness-7 
+        icon: material/brightness-7
         name: Switch to dark mode
     - scheme: slate
       primary: black