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, 3 insertions, 3 deletions

diff --git a/test/t/string.rb b/test/t/string.rb
index c1511de63..447493227 100644
--- a/test/t/string.rb
+++ b/test/t/string.rb
@@ -148,9 +148,9 @@ assert('String#[]=') do
   end
 
   if Object.const_defined?(:Float)
-   e = 'abc'
-   e[1.1] = 'X'
-   assert_equal 'aXc', e
+    e = 'abc'
+    e[1.1] = 'X'
+    assert_equal 'aXc', e
   end
 
   assert_raise(TypeError) { 'a'[0] = 1 }