Fix *some* errors reported by the ESLint no-useless-escape rule

This patch removes unnecessary escape-sequence in (mostly) strings, as a first step, since the ones in regular expressions probably requires more careful testing (just in case).
The only exception is a regular expression in `src/core/annotation.js`, since we should have both unit- and reference-tests for this code *and* given [this information on MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Character_Classes#Types):
 > Inside a character set, the dot loses its special meaning and matches a literal dot.

Please find additional details about the ESLint rule at https://eslint.org/docs/rules/no-useless-escape

src/scripting_api/field.js

@@ -110,8 +110,8 @@ class Field extends PDFObject {
     } catch (error) {
       event.rc = false;
       const value =
-        `\"${error.toString()}\" for event ` +
-        `\"${eventName}\" in object ${this._id}.` +
+        `"${error.toString()}" for event ` +
+        `"${eventName}" in object ${this._id}.` +
         `\n${error.stack}`;
       this._send({ command: "error", value });
     }