Resolve clippy items_after_statements lint

error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:1876:9
         |
    1876 | /         impl<'de> Deserialize<'de> for Field {
    1877 | |             fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    1878 | |             where
    1879 | |                 D: Deserializer<'de>,
    ...    |
    1917 | |             }
    1918 | |         }
         | |_________^
         |
    note: the lint level is defined here
        --> serde/src/lib.rs:95:52
         |
    95   | #![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
         |                                                    ^^^^^^^^^^^^^^^
         = note: `#[deny(clippy::items_after_statements)]` implied by `#[deny(clippy::pedantic)]`
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:1920:9
         |
    1920 |         struct DurationVisitor;
         |         ^^^^^^^^^^^^^^^^^^^^^^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:1922:9
         |
    1922 | /         impl<'de> Visitor<'de> for DurationVisitor {
    1923 | |             type Value = Duration;
    1924 | |
    1925 | |             fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
    ...    |
    1979 | |             }
    1980 | |         }
         | |_________^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:1982:9
         |
    1982 |         const FIELDS: &'static [&'static str] = &["secs", "nanos"];
         |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:2001:9
         |
    2001 | /         impl<'de> Deserialize<'de> for Field {
    2002 | |             fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    2003 | |             where
    2004 | |                 D: Deserializer<'de>,
    ...    |
    2042 | |             }
    2043 | |         }
         | |_________^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:2045:9
         |
    2045 |         struct DurationVisitor;
         |         ^^^^^^^^^^^^^^^^^^^^^^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:2047:9
         |
    2047 | /         impl<'de> Visitor<'de> for DurationVisitor {
    2048 | |             type Value = Duration;
    2049 | |
    2050 | |             fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
    ...    |
    2108 | |             }
    2109 | |         }
         | |_________^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

    error: adding items after statements is confusing, since items exist from the start of the scope
        --> serde/src/de/impls.rs:2111:9
         |
    2111 |         const FIELDS: &'static [&'static str] = &["secs_since_epoch", "nanos_since_epoch"];
         |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
         |
         = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#items_after_statements

serde/src/de/impls.rs

@@ -1871,7 +1871,7 @@ impl<'de> Deserialize<'de> for Duration {
         enum Field {
             Secs,
             Nanos,
-        };
+        }
 
         impl<'de> Deserialize<'de> for Field {
             fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
@@ -1996,7 +1996,7 @@ impl<'de> Deserialize<'de> for SystemTime {
         enum Field {
             Secs,
             Nanos,
-        };
+        }
 
         impl<'de> Deserialize<'de> for Field {
             fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>