feat(CI): add the GitHub Super Linter

The GitHub Super Linter is a more robust and better supported
tool than the current GitHub Actions we are using.

Running these checks:

ERROR_ON_MISSING_EXEC_BIT: true
VALIDATE_BASH: true
VALIDATE_BASH_EXEC: true
VALIDATE_EDITORCONFIG: true
VALIDATE_MARKDOWN: true
VALIDATE_SHELL_SHFMT: true
VALIDATE_YAML: true

https://github.com/marketplace/actions/super-linter
https://github.com/github/super-linter

Added the GitHub Super Linter badge to the README.

Also updated the pre-commit framework and added
more documentation on pre-commit.

Added one more pre-commit check: check-executables-have-shebangs

Added one extra check for merge conflicts to our
GitHub Actions.

EditorConfig and Markdown linting.

Minor grammar and spelling fixes.

Update linter.yml

1 files changed, 8 insertions, 8 deletions

diff --git a/test/t/module.rb b/test/t/module.rb
index 07d550804..9aa018280 100644
--- a/test/t/module.rb
+++ b/test/t/module.rb
@@ -391,15 +391,15 @@ assert('Module#undef_method', '15.2.2.4.42') do
     class Parent
       def hello
       end
-     end
+    end
 
-     class Child < Parent
+    class Child < Parent
       def hello
       end
-     end
+    end
 
-     class GrandChild < Child
-     end
+    class GrandChild < Child
+    end
   end
   Test4UndefMethod::Child.class_eval{ undef_method :hello }
 
@@ -736,9 +736,9 @@ assert('Issue 1467') do
 
   class C1
     include M1
-     def initialize()
-       super()
-     end
+      def initialize()
+        super()
+      end
   end
 
   class C2