========================================

Support trim

• String
• Vec<String>
• Option<String>

how to use

```rust fn main() { #[derive(Deserialize)] struct Foo { #[serde(deserializewith = "stringtrim")] name: String, } let json = r#"{"name":" "}"#; let foo = serdejson::fromstr::(json).unwrap(); assert_eq!(foo.name, "");

#[derive(Deserialize)]
struct OptionFoo {
    #[serde(deserialize_with = "option_string_trim")]
    name: Option<String>,
}
let json = r#"{"name":" "}"#;
let foo = serde_json::from_str::<OptionFoo>(json).unwrap();
assert_eq!(foo.name, None);

#[derive(Deserialize)]
struct OptionBar {
    #[serde(default, deserialize_with = "option_string_trim")]
    name: Option<String>,
    addr: String,
}
let json = r#"{"addr":"ABC"}"#;
let foo = serde_json::from_str::<OptionBar>(json).unwrap();
assert_eq!(foo.name, None);
assert_eq!(foo.addr, "ABC");

#[derive(Deserialize)]
struct VecFoo {
    #[serde(deserialize_with = "vec_string_trim")]
    name: Vec<String>,
}
let json = r#"{"name":["   ","foo","b ar","hello ","  rust"]}"#;
let foo = serde_json::from_str::<VecFoo>(json).unwrap();
assert_eq!(foo.name, vec!["", "foo", "b ar", "hello", "rust"]);

} ```