Make mentionRegex stricter

[HoodieRocks]

Description

This pull request addresses an issue where the existing mentionRegex was being matched in unintended contexts, such as emails and URLs containing the "@" symbol. The proposed changes make the mentionRegex stricter to prevent false positives and improve the accuracy of mentions in the remark-mentions plugin.

Changes Made

• Modified the mentionRegex to make it stricter and prevent unintended matches in emails and URLs containing "@" symbols.
• Added a new test case to validate the correctness of the updated mentionRegex implementation.

Checklist

• Updated mentionRegex to be stricter and more accurate.
• Added a new test case to cover the changes.
• Verified that all existing tests pass with the updated regex.
• Ran the test suite locally to ensure compatibility.

This pull request aims to enhance the accuracy of the remark-mentions plugin and improve its behaviour when dealing with mentions in various contexts. Please review and provide feedback.

Thank you!

[FinnRG]

Thank you for your PR. Lookbehind assertions have only recently gained support in safari, so could you maybe replace (?<!\S) with just \s or would this introduce other edge cases?

[HoodieRocks]

\s can capture a leading space, which messes up parsing, resulting in something like:

source:   'This is @test'
expected: 'This is [**@test**](/test)\n'
actual:   'This is[** @test**](/test)\n'

Any mention that's at the beginning of a line won't be picked up, but that can be fixed with ($:^|\s).

Do you have a suggestion for trimming the space?

[FinnRG]

@HoodieRocks Good point, what if we use (?:^|\s) and separate the leading white space in the replaceMention function like this (just a rough draft):

  function replaceMention(value, username) {
    let whitespace = [];
    // Separate leading white space
    if (value.indexOf("@") > 0) {
      whitespace.push({
        type: "text",
        value: value.substring(0, value.indexOf("@")),
      });
    }

    return [
      ...whitespace,
      {
        type: "link",
        url: opts.usernameLink(username),
        children: [
          { type: "strong", children: [{ type: "text", value: value.trim() }] }, // Trim the username here
        ],
      },
    ];
  }

[HoodieRocks]

That code worked perfectly. The only difference I made was adding the type.

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (0ff4c57) 100.00% compared to head (442a571) 100.00%.
Report is 3 commits behind head on main.

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Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files            2         2           
  Lines           48        66   +18     
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+ Hits            48        66   +18     

Files Changed	Coverage Δ
lib/index.js	100.00% <100.00%> (ø)

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[FinnRG]

Thank you for your PR. I'll publish version 1.1 shortly.