Fix a pubrules error, and have spec-prod check for that in PRs.

Also adjust editorconfig to indent workflows correctly.

Author: jyasskin

.editorconfig

@@ -9,3 +9,7 @@ indent_size = 4
 end_of_line = lf
 insert_final_newline = true
 trim_trailing_whitespace = true
+
+[*.yml]
+indent_style = space
+indent_size = 2

.github/workflows/build.yml

@@ -20,3 +20,5 @@ jobs:
           W3C_BUILD_OVERRIDE: |
             status: NOTE
             metadata order: *, !*
+            metadata include: Participate no, Feedback yes
+          VALIDATE_PUBRULES: true