Update example class syntax to account for Prettier-formatting

Style-Guide.md

@@ -1,6 +1,6 @@
 This page outlines the style conventions that PDF.js follows to maintain a consistent code base. We ask each contributor that creates a pull request to adhere to these conventions.  
 
-Most of these conventions are checked automatically by a linter (Prettier) after each push to a branch of a pull request. Refer to https://github.com/mozilla/pdf.js/wiki/Contributing#4-run-lint-and-testing for information about running the linter locally.
+Most of these conventions are checked automatically by a linter (ESLint/Prettier) after each push to a branch of a pull request. Refer to https://github.com/mozilla/pdf.js/wiki/Contributing#4-run-lint-and-testing for information about running the linter locally.
 
 ## General
 * Indentation: 2 spaces
@@ -57,8 +57,11 @@ class ClassName {
     ...
   }
 
-  aVeryVeryVeryVeryVeryLongFunctionName
-      (arg1, arg2, ...) {
+  aVeryVeryVeryVeryVeryLongFunctionName(
+    arg1,
+    arg2,
+    ...
+  ) {
     ...
   }
 }
@@ -77,8 +80,11 @@ var ClassName = (function ClassNameClosure() {
       ...
     },
 
-    aVeryVeryVeryVeryVeryLongFunctionName
-        (arg1, arg2, ...) {
+    aVeryVeryVeryVeryVeryLongFunctionName(
+      arg1,
+      arg2,
+      ...
+    ) {
       ...
     },
   };