Sdl2TtfContext should need lifetime

[ZengGengSen]

pub struct FontManager<'ttf_module> {
    ttf_ctx: sdl2::ttf::Sdl2TtfContext,
    fonts: HashMap<String, sdl2::ttf::Font<'ttf_module, 'static>>,
}

impl<'ttf_module> FontManager<'ttf_module> {
    pub fn new() -> Result<Self, Error> {
        let ttf_ctx = sdl2::ttf::init()?;

        Ok(Self {
            ttf_ctx,
            fonts: HashMap::new(),
        })
    }

    pub fn load_font<P: AsRef<std::path::Path>>(
        &mut self,
        path: P,
        name: &str,
        point_size: u16,
    ) -> Result<&mut sdl2::ttf::Font<'ttf_module, 'static>, Error> {
        let font = self.ttf_ctx.load_font(path, point_size);
        // lifetime error
        self.fonts.insert(name.to_string(), font?);
        Ok(self.fonts.get_mut(name).unwrap())
    }
}