Use Not::not rather than a custom is_false function

The `is_false` function already exists in the standard library, as
`Not::not`; use that in `skip_serializing_if` rather than defining an
`is_false` function.

Author: joshtriplett

crates/cargo-util-schemas/src/manifest/mod.rs

@@ -1496,7 +1496,7 @@ impl TomlPlatform {
 #[derive(Serialize, Debug, Clone)]
 #[cfg_attr(feature = "unstable-schema", derive(schemars::JsonSchema))]
 pub struct InheritableLints {
-    #[serde(skip_serializing_if = "is_false")]
+    #[serde(skip_serializing_if = "std::ops::Not::not")]
     #[cfg_attr(feature = "unstable-schema", schemars(default))]
     pub workspace: bool,
     #[serde(flatten)]
@@ -1513,10 +1513,6 @@ impl InheritableLints {
     }
 }
 
-fn is_false(b: &bool) -> bool {
-    !b
-}
-
 impl<'de> Deserialize<'de> for InheritableLints {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
     where

crates/crates-io/lib.rs

@@ -82,14 +82,10 @@ pub struct NewCrateDependency {
     pub artifact: Option<Vec<String>>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub bindep_target: Option<String>,
-    #[serde(default, skip_serializing_if = "is_false")]
+    #[serde(default, skip_serializing_if = "std::ops::Not::not")]
     pub lib: bool,
 }
 
-fn is_false(x: &bool) -> bool {
-    *x == false
-}
-
 #[derive(Deserialize)]
 pub struct User {
     pub id: u32,