doc: use stricter indentation checking for docs

Use stricter ESLint indent checking for sample code in docs.

PR-URL: #13950
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/.eslintrc.yaml

@@ -13,3 +13,13 @@ rules:
   no-var: 2
   prefer-const: 2
   prefer-rest-params: 2
+
+  # use stricter indent over indent-legacy
+  indent-legacy: 0
+  indent: [2, 2, {ArrayExpression: first,
+                  CallExpression: {arguments: first},
+                  FunctionDeclaration: {parameters: first},
+                  FunctionExpression: {parameters: first},
+                  MemberExpression: off,
+                  ObjectExpression: first,
+                  SwitchCase: 1}]