Add support for single-quoted strings in mojangson parser

[Copilot]

Fixes parsing errors when NBT data contains strings surrounded by single quotes instead of double quotes.

Problem

The parser was failing to parse valid Minecraft NBT strings that use single quotes (') instead of double quotes ("). According to the Minecraft NBT format specification, single quotes are valid string delimiters.

This was causing errors like:

Error: Error parsing text '{"minecraft:custom_name":'":!!: book :!!:"'}'
    at Parser.feed

Examples that were failing:

• {key:'value'}
• {"minecraft:custom_name":'":!!: book :!!:"'}
• Items with custom names that contain special characters

Solution

Extended the grammar to support single-quoted strings while maintaining backward compatibility:

1. Added SINGLE_QUOTED_STRING grammar rule - Handles single-quoted strings with proper escape sequence support (including \', \", \n, \r, \t, \b, \f, \/, \\, and unicode escapes)

2. Implemented disambiguation logic - When single-quoted content can be parsed as either a plain string or a compound object (e.g., '{"text":"..."}'), the parser now prefers the structured interpretation (compound), matching Minecraft's behavior

3. Added comprehensive tests - 7 new test cases covering various single-quote scenarios

Examples

Now works correctly:

const mojangson = require('mojangson')

// Simple single-quoted string
mojangson.parse("{key:'value'}")
// Returns: { type: 'compound', value: { key: { value: 'value', type: 'string' } } }

// Single-quoted string with special characters  
mojangson.parse('{"minecraft:custom_name":\'":!!: book :!!:"\'}')
// Returns: { type: 'compound', value: { 'minecraft:custom_name': { value: '":!!: book :!!:"', type: 'string' } } }

// Single-quoted JSON (parsed as compound, not string)
mojangson.parse('\'{"text":"hello"}\'')
// Returns: { type: 'compound', value: { text: { value: 'hello', type: 'string' } } }

Testing

• ✅ All 117 existing tests continue to pass
• ✅ 7 new tests for single-quote support
• ✅ Total: 124 tests passing

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Single quote strings</issue_title>
<issue_description>Hello!

Thanks for this library! It has been very helpful.

I've ran into a problem involving strings that are surrounded by single quotes.
Examples
{key:'value'}
{"minecraft:custom_name":'":!!: book :!!:"'}

Error: Error parsing text '{"minecraft:custom_name":'":!!: book :!!:"'}'
    at Parser.feed (C:\Users\mike-\Documents\Projects\CMC_Stuff\AuctionMonitor\test_server\node_modules\nearley\lib\nearley.js:343:27)
    at Module.parse (C:\Users\mike-\Documents\Projects\CMC_Stuff\AuctionMonitor\test_server\node_modules\mojangson\index.js:94:14)
    at file:///C:/Users/mike-/Documents/Projects/CMC_Stuff/AuctionMonitor/test_server/snbt-parse-example.js:10:45
    at ModuleJob.run (node:internal/modules/esm/module_job:377:25)
    at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:691:26)
    at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5) {
  offset: 26,
  token: { value: '"' }

This has been happening for items with custom names.

Apparently it's valid for strings to sometimes be surrounded by single quotes instead of double quotes
https://minecraft.wiki/w/NBT_format

</issue_description>

<agent_instructions>update grammar and add test for single quote strings</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes #52

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[BadgerCode]

Tested this myself and it does fix my original problem