Resolve redundant_closure_for_method_calls pedantic clippy lint

    warning: redundant closure
      --> gen/src/cfg.rs:64:45
       |
    64 |             let value = string.as_ref().map(|string| string.value());
       |                                             ^^^^^^^^^^^^^^^^^^^^^^^ help: replace the closure with the method itself: `syn::LitStr::value`
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_closure_for_method_calls
       = note: `-W clippy::redundant-closure-for-method-calls` implied by `-W clippy::pedantic`

gen/build/src/lib.rs

@@ -66,7 +66,6 @@
     clippy::nonminimal_bool,
     clippy::option_if_let_else,
     clippy::or_fun_call,
-    clippy::redundant_closure_for_method_calls,
     clippy::redundant_else,
     clippy::semicolon_if_nothing_returned,
     clippy::shadow_unrelated,

gen/cmd/src/main.rs

@@ -18,7 +18,6 @@
     clippy::nonminimal_bool,
     clippy::option_if_let_else,
     clippy::or_fun_call,
-    clippy::redundant_closure_for_method_calls,
     clippy::redundant_else,
     clippy::semicolon_if_nothing_returned,
     clippy::shadow_unrelated,

gen/lib/src/lib.rs

@@ -29,7 +29,6 @@
     clippy::nonminimal_bool,
     clippy::option_if_let_else,
     clippy::or_fun_call,
-    clippy::redundant_closure_for_method_calls,
     clippy::redundant_else,
     clippy::semicolon_if_nothing_returned,
     clippy::shadow_unrelated,

gen/src/cfg.rs

@@ -4,7 +4,7 @@ use crate::syntax::report::Errors;
 use crate::syntax::Api;
 use quote::quote;
 use std::collections::BTreeSet as Set;
-use syn::Error;
+use syn::{Error, LitStr};
 
 pub(super) struct UnsupportedCfgEvaluator;
 
@@ -61,7 +61,7 @@ fn try_eval(cfg_evaluator: &dyn CfgEvaluator, expr: &CfgExpr) -> Result<bool, Ve
         CfgExpr::Unconditional => Ok(true),
         CfgExpr::Eq(ident, string) => {
             let key = ident.to_string();
-            let value = string.as_ref().map(|string| string.value());
+            let value = string.as_ref().map(LitStr::value);
             match cfg_evaluator.eval(&key, value.as_deref()) {
                 CfgResult::True => Ok(true),
                 CfgResult::False => Ok(false),