Add EditorConfig file

More info here: https://editorconfig.org/

For example, `ruby/ruby` has it: https://github.com/ruby/ruby/blob/05ebaee/.editorconfig

Also fix some offenses.

.editorconfig

@@ -0,0 +1,13 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+max_line_length = 80
+
+[*.zsh]
+indent_size = 4

README.md

@@ -57,4 +57,3 @@ To install this gem onto your local machine, run `bundle exec rake install`. To
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/optparse.
-

misc/rb_optparse.bash

@@ -16,5 +16,5 @@ _rb_optparse() {
 }
 
 rb_optparse () {
-    [ $# = 0 ] || complete -o default -F _rb_optparse "$@"
+  [ $# = 0 ] || complete -o default -F _rb_optparse "$@"
 }

misc/rb_optparse.zsh

@@ -24,8 +24,8 @@ generate-complete-function/ruby/optparse ()
     mkdir -p "${ZSH_COMPLETION_DIR-$HOME/.zsh.d/Completion}"
     $1 "--*-completion-zsh=${1:t}" >! "${ZSH_COMPLETION_DIR-$HOME/.zsh.d/Completion}/$cmpl"
     if [[ $(type -w "$cmpl") == "${cmpl}: function" ]]; then
-	unfunction "$cmpl"
-	autoload -U "$cmpl"
+        unfunction "$cmpl"
+        autoload -U "$cmpl"
     else
         compinit "$cmpl"
     fi

test/optparse/test_acceptable.rb

@@ -196,4 +196,3 @@ def test_decimal_numeric
   end
 
 end
-