Resolve some needless_lifetimes clippy lints

    warning: the following explicit lifetimes could be elided: 'a
        --> src/de.rs:1381:11
         |
    1381 | impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
         |           ^^                                           ^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
         = note: `-W clippy::needless-lifetimes` implied by `-W clippy::all`
         = help: to override `-W clippy::all` add `#[allow(clippy::needless_lifetimes)]`
    help: elide the lifetimes
         |
    1381 - impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
    1381 + impl<'de, R: Read<'de>> de::Deserializer<'de> for &mut Deserializer<R> {
         |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/map.rs:418:6
        |
    418 | impl<'a, Q> ops::Index<&'a Q> for Map<String, Value>
        |      ^^                 ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    418 - impl<'a, Q> ops::Index<&'a Q> for Map<String, Value>
    418 + impl<Q> ops::Index<&Q> for Map<String, Value>
        |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/map.rs:441:6
        |
    441 | impl<'a, Q> ops::IndexMut<&'a Q> for Map<String, Value>
        |      ^^                    ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    441 - impl<'a, Q> ops::IndexMut<&'a Q> for Map<String, Value>
    441 + impl<Q> ops::IndexMut<&Q> for Map<String, Value>
        |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/value/index.rs:140:10
        |
    140 |     impl<'a, T> Sealed for &'a T where T: ?Sized + Sealed {}
        |          ^^                 ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    140 -     impl<'a, T> Sealed for &'a T where T: ?Sized + Sealed {}
    140 +     impl<T> Sealed for &T where T: ?Sized + Sealed {}
        |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/number.rs:612:11
        |
    612 | impl<'de, 'a> Deserializer<'de> for &'a Number {
        |           ^^                         ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    612 - impl<'de, 'a> Deserializer<'de> for &'a Number {
    612 + impl<'de> Deserializer<'de> for &Number {
        |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/read.rs:754:6
        |
    754 | impl<'a, 'de, R> private::Sealed for &'a mut R where R: Read<'de> {}
        |      ^^                               ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    754 - impl<'a, 'de, R> private::Sealed for &'a mut R where R: Read<'de> {}
    754 + impl<'de, R> private::Sealed for &mut R where R: Read<'de> {}
        |

    warning: the following explicit lifetimes could be elided: 'a
       --> src/read.rs:756:6
        |
    756 | impl<'a, 'de, R> Read<'de> for &'a mut R
        |      ^^                         ^^
        |
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
    help: elide the lifetimes
        |
    756 - impl<'a, 'de, R> Read<'de> for &'a mut R
    756 + impl<'de, R> Read<'de> for &mut R
        |

src/de.rs

@@ -1378,7 +1378,7 @@ macro_rules! check_recursion {
     };
 }
 
-impl<'de, 'a, R: Read<'de>> de::Deserializer<'de> for &'a mut Deserializer<R> {
+impl<'de, R: Read<'de>> de::Deserializer<'de> for &mut Deserializer<R> {
     type Error = Error;
 
     #[inline]

src/map.rs

@@ -415,7 +415,7 @@ impl Hash for Map<String, Value> {
 /// }
 /// # ;
 /// ```
-impl<'a, Q> ops::Index<&'a Q> for Map<String, Value>
+impl<Q> ops::Index<&Q> for Map<String, Value>
 where
     String: Borrow<Q>,
     Q: ?Sized + Ord + Eq + Hash,
@@ -438,7 +438,7 @@ where
 /// #
 /// map["key"] = json!("value");
 /// ```
-impl<'a, Q> ops::IndexMut<&'a Q> for Map<String, Value>
+impl<Q> ops::IndexMut<&Q> for Map<String, Value>
 where
     String: Borrow<Q>,
     Q: ?Sized + Ord + Eq + Hash,

src/number.rs

@@ -609,7 +609,7 @@ impl<'de> Deserializer<'de> for Number {
     }
 }
 
-impl<'de, 'a> Deserializer<'de> for &'a Number {
+impl<'de> Deserializer<'de> for &Number {
     type Error = Error;
 
     deserialize_any!(ref);

src/read.rs

@@ -751,9 +751,9 @@ impl<'a> Read<'a> for StrRead<'a> {
 
 //////////////////////////////////////////////////////////////////////////////
 
-impl<'a, 'de, R> private::Sealed for &'a mut R where R: Read<'de> {}
+impl<'de, R> private::Sealed for &mut R where R: Read<'de> {}
 
-impl<'a, 'de, R> Read<'de> for &'a mut R
+impl<'de, R> Read<'de> for &mut R
 where
     R: Read<'de>,
 {

src/value/index.rs

@@ -137,7 +137,7 @@ mod private {
     impl Sealed for usize {}
     impl Sealed for str {}
     impl Sealed for alloc::string::String {}
-    impl<'a, T> Sealed for &'a T where T: ?Sized + Sealed {}
+    impl<T> Sealed for &T where T: ?Sized + Sealed {}
 }
 
 /// Used in panic messages.