fix(lsp-ui-doc): prevent filling of markdown code blocks

[tempdragon]

Problem Description

The function signatures in Rust, if containing a signature with lengthy parameter names, may fail to show the markdown newlines.
Here is a demonstration:

/// An preprocessing pipeline to serialize each step of handling.
/// # Arguments
/// * `df`:
/// * `config`:
/// * `classification`:
/// * `is_update`:
/// * `per_info_max_ts`:
/// * `force_recalculate_methods`:
/// * `force_recalculate_stats`:
/// * `no_main_regen`:
/// * `no_aux_regen`:
fn my_test() {}
/// An preprocessing pipeline to serialize each step of handling.
/// # Arguments
/// * `df`:
/// * `config`:
/// * `classification`:
/// * `is_update`:
/// * `per_info_max_ts`:
/// * `force_recalculate_methods`:
/// * `force_recalculate_stats`:
/// * `no_main_regen`:
/// * `no_aux_regen`:
#[allow(clippy::too_many_arguments)]
pub async fn process_pipeline(
    mut df: DataFrame,
    config: &Config,
    classification: &Classification,
    is_update: bool,
    per_info_max_ts: Option<FxHashMap<(u8, u32), u32>>,
    force_recalculate_methods: bool,
    force_recalculate_stats: bool,
    no_main_regen: bool,
    no_aux_regen: bool,
) -> Result<usize> {
}

The result of two different functions as a comparison

Solution

I refactor lsp-ui-doc--fill-document to skip fenced code blocks and add lsp-ui-doc--fill-check-and-fill for safer paragraph wrapping. This prevents aggressive reflowing of code signatures while maintaining proper text wrapping for prose.