fix(console): escape backquotes in MDX context

[siketyan]

Summary

Fixes biomejs/website#1391

Backquotes (`) were needed to be escaped in MDX, otherwise it may cause invisible backquotes or broken markups.

Test Plan

Used the updated biome_console crate in the website repository to see if it works on my machine.

Docs

N/A

[changeset-bot]

⚠️ No Changeset found

Latest commit: d42e1b9

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[siketyan]

I would skip a changeset because we don't support any direct usages of our internal crates, and there are no user-facing interface that emits a markup for MDX.

[coderabbitai]

Walkthrough

The change modifies the HTML output writer in the console crate to properly escape backtick characters when MDX mode is enabled. Previously, backticks were left unescaped in MDX output; now they are emitted as ` to match the existing HTML escape sequences. This resolves documentation rendering issues where template literal examples were incorrectly displayed due to missing backtick escapes.

Suggested labels

L-HTML

Suggested reviewers

• Conaclos
• ematipico

Pre-merge checks and finishing touches

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title Check	✅ Passed	The title "fix(console): escape backquotes in MDX context" directly and clearly describes the primary change in the pull request. It specifies what is being fixed (escaping backquotes), which component is affected (console), and the context where it applies (MDX). The title is concise, avoids vague terminology, and provides sufficient clarity for scanning commit history.
Linked Issues Check	✅ Passed	The code changes directly address the requirements in linked issue #1391. The issue identifies HTML escaping problems in documentation examples for the useTemplate lint rule, expecting fixes to be correctly escaped. The modification to crates/biome_console/src/write/html.rs implements backtick escaping in MDX mode (emitting ` instead of raw backticks), which resolves the escaping issue preventing correct rendering of documentation examples.
Out of Scope Changes Check	✅ Passed	The changes are narrowly scoped to the stated objective of fixing backquote escaping in MDX. The modification to crates/biome_console/src/write/html.rs adds support for escaping backticks when with_mdx is enabled, directly addressing the HTML escaping issue described in issue #1391. No extraneous changes or unrelated modifications appear to be present.
Description Check	✅ Passed	The pull request description is clearly related to the changeset and effectively communicates what's being fixed. It specifically describes the problem (backquotes in MDX causing invisible characters or broken markup), references the exact issue being resolved (#1391), and provides concrete evidence through a test screenshot. The description aligns well with the code changes that add backtick escaping to the MDX HTML rendering path in the biome_console crate. The level of detail is appropriate and the content is directly relevant to the modifications made.

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[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (1)

crates/biome_console/src/write/html.rs (1)

122-122: LGTM! Backtick escaping correctly added.

The change properly escapes backticks in MDX mode using the correct HTML entity. This matches the existing pattern for other MDX-specific escapes and directly addresses the documentation rendering issue.

However, consider adding a test case to verify backtick escaping works correctly, similar to the existing tests for curly braces and newlines.

Example test to add at the end of the test module:

#[test]
fn escape_backticks() {
    let mut buf = Vec::new();
    let mut writer = super::HTML(&mut buf, false).with_mdx();
    let mut formatter = Formatter::new(&mut writer);

    formatter
        .write_markup(markup! {
            "Template literal: `foo`"
        })
        .unwrap();

    assert_eq!(
        String::from_utf8(buf).unwrap(),
        "Template literal: `foo`"
    );
}

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📒 Files selected for processing (1)

• crates/biome_console/src/write/html.rs (1 hunks)

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**/*.{rs,toml}

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Files:

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🧠 Learnings (1)

📚 Learning: 2025-10-15T09:22:46.002Z

Learnt from: CR
Repo: biomejs/biome PR: 0
File: crates/biome_js_formatter/CONTRIBUTING.md:0-0
Timestamp: 2025-10-15T09:22:46.002Z
Learning: Applies to crates/biome_js_formatter/**/*.rs : Use `dbg_write!` to debug and inspect the emitted IR during formatting

Applied to files:

• crates/biome_console/src/write/html.rs

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