ParseException when text input starts with special character

[danielfowler]

Describe the bug
I have a Twitter handle field input for users and some are including the @ symbol at the start of their input. Workshop isn't wrapping the resultant string in quotes, which is throwing a ParseException upon trying to load the value in template.

To Reproduce
Steps to reproduce the behavior:

1. Fresh install of Statamic
2. Add Workshop
3. Create a text input like <input name="twitter"/>
4. Load in browser and save text input value like @statamic
5. Load any page in browser

Expected behavior
String value would save as twitter: "@statamic" and page would load

Screenshots
If applicable, add screenshots to help explain your problem.

Environment details (please complete the following information):

• Workshop Version 1.1.3
• Statamic Version 2.11.13
• Fresh Install or Upgrade: Fresh
• OS: [e.g. macOS 10.12.6, Ubuntu 16.04] Windows 10
• Browser: [e.g. chrome, safari] Firefox
• Web Server: [eg. Apache, Nginx, Valet] Valet
• PHP Version: [eg. 7.1] 7.2

Additional context
Technically this is happening through the Profiler add-on, but it's using the Workshop engine to save values to user files.

Error stack trace:

ParseException in Inline.php line 334: The reserved indicator "@" cannot start a plain scalar; you need to quote the scalar at line 18 (near "instagram: @justclawsonthings").

    in Inline.php line 334
    at Inline::parseScalar('@justclawsonthings', '0', null, '18', true, array()) in Inline.php line 109
    at Inline::parse('@justclawsonthings', '0', array()) in Parser.php line 757
    at Parser->parseValue('@justclawsonthings', '0', 'mapping') in Parser.php line 354
    at Parser->doParse('6167381437', '0') in Parser.php line 105

[danielfowler]

I'm troubleshooting a bunch of errors right now, so please excuse my sudden run on issue reporting.

Update: it seems all leading special characters in text inputs aren't being escaped on save. I'm seeing issues with strings that contain apostrophes and/or quotation marks start with special characters.

A couple examples:

• hair: "dirty" blonde
• acting_experience: "Annie Jr." in 2018
• tech_experience: `None
• twitter: @danielfowler