seo: fix multiline blocks in yaml frontmatters

Author: avivace

list/README.md

@@ -6,8 +6,10 @@ head:
       content: gbdev.io homepage
   - - meta
     - name: og:description
-      content: Home of the Game Boy and Game Boy Advance homebrew development scene.
-We are working on (open) development tools, documentation and digital preservation.
+      content: >
+        Home of the Game Boy and Game Boy Advance homebrew development scene.
+        We are working on (open) development tools, documentation and digital
+        preservation.
 ---
 
 <div id='outer'>

list/gbcompo21.md

@@ -5,7 +5,9 @@ head:
       content: GB Compo 2021
   - - meta
     - name: og:description
-      content: An OG game competition! Create original games, demos, homebrews tools and music for the original Game Boy / Game Boy Color and compete for glory (and a lot of prizes)!
+      content: >
+        An OG game competition! Create original games, demos, homebrews tools and music
+        for the original Game Boy / Game Boy Color and compete for glory (and a lot of prizes)!
 ---
 
 # Game Boy Competition 2021