You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: one_liner.rs
    path of file: ./repos/ruff/crates/ruff_linter/src/rules/pydocstyle/rules
    
    the code of the file until where you have to start completion: use ruff_diagnostics::{Diagnostic, Edit, Fix, FixAvailability, Violation};
use ruff_macros::{derive_message_formats, violation};
use ruff_python_ast::str::{leading_quote, trailing_quote};
use ruff_source_file::NewlineWithTrailingNewline;
use ruff_text_size::Ranged;

use crate::checkers::ast::Checker;
use crate::docstrings::Docstring;

/// ## What it does
/// Checks for single-line docstrings that are broken across multiple lines.
///
/// ## Why is this bad?
/// [PEP 257] recommends that docstrings that _can_ fit on one line should be
/// formatted on a single line, for consistency and readability.
///
/// ## Example
/// ```py
    
pub(crate) fn one_liner(checker: &mut Checker, docstring: &Docstring) {
    let mut line_count = 0;
    let mut non_empty_line_count = 0;
    for line in NewlineWithTrailingNewline::from(docstring.body().as_str()) {
        line_count += 1;
        if !line.trim().is_empty() {
            non_empty_line_count += 1;
        }
        if non_empty_line_count > 1 {
            return;
        }
    }

    if non_empty_line_count == 1 && line_count > 1 {
        let mut diagnostic = Diagnostic::new(FitsOnOneLine, docstring.range());
        if let (Some(leading), Some(trailing)) = (
            leading_quote(docstring.contents),
            trailing_quote(docstring.contents),
        ) {
            // If removing whitespace would lead to an invalid string of quote
            // characters, avoid applying the fix.
            let body = docstring.body();
            let trimmed = body.trim();
            if trimmed.chars().rev().take_while(|c| *c == '\\').count() % 2 == 0
                && !trimmed.ends_with(trailing.chars().last().unwrap())
                && !trimmed.starts_with(leading.chars().last().unwrap())
            {
                diagnostic.set_fix(Fix::unsafe_edit(Edit::range_replacement(
                    format!("{leading}{trimmed}{trailing}"),
                    docstring.range(),
                )));
            }
        }
        checker.diagnostics.push(diagnostic);
    }
}