add prettierrc and editorconfig for consistent formatting

.editorconfig

@@ -0,0 +1,11 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.php]
+charset = utf-8
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 4

.prettierrc

@@ -0,0 +1,9 @@
+{
+  "printWidth": 120,
+  "phpVersion": "7.2",
+  "trailingCommaPHP": false,
+  "trailingComma": "none",
+  "semi": false,
+  "singleQuote": true,
+  "endOfLine": "lf"
+}

src/N.php

@@ -2,7 +2,8 @@
 
 namespace Shovel;
 
-class N {
+class N
+{
     public static function toInt($n): ?int
     {
         return $n === null ? null : intval($n);

src/S.php

@@ -123,12 +123,14 @@ public static function trim(string $data): string
     }
 
     // S::replace("a", "b", "appletini") -> "bppletini"
-    public static function replace(string $old, string $new, string $data): string {
+    public static function replace(string $old, string $new, string $data): string
+    {
         return str_replace($old, $new, $data);
     }
 
     // S::splitAt(3, "abcdef") -> ["abc", "def"]
-    public static function splitAt(int $index, string $data): array {
+    public static function splitAt(int $index, string $data): array
+    {
         $first = self::slice(0, $index, $data);
         $second = self::slice($index, PHP_INT_MAX, $data);
         return [$first, $second];