Do not indent backtick quoted strings in code blocks (#492)

* Do not indent backtick quoted strings in initializer or rule action code blocks
* Use const instead of var for ESLint happiness
* Fix ESLint issues for double quotes and indent6

lib/compiler/passes/generate-js.js

@@ -6,9 +6,10 @@ let op = require("../opcodes");
 
 // Generates parser JavaScript code.
 function generateJS(ast, options) {
-  // These only indent non-empty lines to avoid trailing whitespace.
+  /* These only indent non-empty lines to avoid trailing whitespace. */
-  function indent2(code)  { return code.replace(/^(.+)$/gm, "  $1");         }
+  const lineMatchRE = /^([^`\r\n]+?(?:`[^`]*?`[^\r\n]*?)?)$/gm;
-  function indent10(code) { return code.replace(/^(.+)$/gm, "          $1"); }
+  function indent2(code)  { return code.replace(lineMatchRE, "  $1");         }
+  function indent10(code) { return code.replace(lineMatchRE, "          $1"); }
 
   function generateTables() {
     if (options.optimize === "size") {