test: update webpack-4 snaps

Author: snitin315

test/__snapshots__/validate-options.test.js.snap.webpack4

@@ -559,7 +559,8 @@ exports[`options validate should throw an error on the "static" option with '' v
 exports[`options validate should throw an error on the "static" option with '{"directory":false}' value 1`] = `
 "ValidationError: Invalid options object. Dev Server has been initialized using an options object that does not match the API schema.
  - options.static.directory should be a non-empty string.
-   -> Directory for static contents."
+   -> Directory for static contents.
+   -> Read more at https://webpack.js.org/configuration/dev-server/#directory"
 `;
 
 exports[`options validate should throw an error on the "static" option with '{"publicPath":false}' value 1`] = `
@@ -572,6 +573,7 @@ exports[`options validate should throw an error on the "static" option with '{"p
     * options.static.publicPath should be one of these:
       [string, ...] (should not have fewer than 1 item) | string
       -> The static files will be available in the browser under this public path.
+      -> Read more at https://webpack.js.org/configuration/dev-server/#publicpath
       Details:
        * options.static.publicPath should be an array:
          [string, ...] (should not have fewer than 1 item)
@@ -588,6 +590,7 @@ exports[`options validate should throw an error on the "static" option with '{"s
     * options.static.serveIndex should be one of these:
       boolean | object { … }
       -> Tells dev server to use serveIndex middleware when enabled.
+      -> Read more at https://webpack.js.org/configuration/dev-server/#serveindex
       Details:
        * options.static.serveIndex should be a boolean.
        * options.static.serveIndex should be an object:
@@ -604,6 +607,7 @@ exports[`options validate should throw an error on the "static" option with '{"w
     * options.static.watch should be one of these:
       boolean | object { … }
       -> Watches for files in static content directory.
+      -> Read more at https://webpack.js.org/configuration/dev-server/#watch
       Details:
        * options.static.watch should be a boolean.
        * options.static.watch should be an object: