Resolve manual_strip clippy lint

src/de.rs

@@ -951,38 +951,35 @@ where
     if v == "false" {
         return visitor.visit_bool(false);
     }
-    if v.starts_with("0x") || v.starts_with("+0x") {
-        let start = 2 + v.starts_with('+') as usize;
-        if let Ok(n) = u64::from_str_radix(&v[start..], 16) {
+    if let Some(rest) = Option::or(v.strip_prefix("0x"), v.strip_prefix("+0x")) {
+        if let Ok(n) = u64::from_str_radix(rest, 16) {
             return visitor.visit_u64(n);
         }
     }
-    if v.starts_with("-0x") {
-        let negative = format!("-{}", &v[3..]);
+    if let Some(rest) = v.strip_prefix("-0x") {
+        let negative = format!("-{}", rest);
         if let Ok(n) = i64::from_str_radix(&negative, 16) {
             return visitor.visit_i64(n);
         }
     }
-    if v.starts_with("0o") || v.starts_with("+0o") {
-        let start = 2 + v.starts_with('+') as usize;
-        if let Ok(n) = u64::from_str_radix(&v[start..], 8) {
+    if let Some(rest) = Option::or(v.strip_prefix("0o"), v.strip_prefix("+0o")) {
+        if let Ok(n) = u64::from_str_radix(rest, 8) {
             return visitor.visit_u64(n);
         }
     }
-    if v.starts_with("-0o") {
-        let negative = format!("-{}", &v[3..]);
+    if let Some(rest) = v.strip_prefix("-0o") {
+        let negative = format!("-{}", rest);
         if let Ok(n) = i64::from_str_radix(&negative, 8) {
             return visitor.visit_i64(n);
         }
     }
-    if v.starts_with("0b") || v.starts_with("+0b") {
-        let start = 2 + v.starts_with('+') as usize;
-        if let Ok(n) = u64::from_str_radix(&v[start..], 2) {
+    if let Some(rest) = Option::or(v.strip_prefix("0b"), v.strip_prefix("+0b")) {
+        if let Ok(n) = u64::from_str_radix(rest, 2) {
             return visitor.visit_u64(n);
         }
     }
-    if v.starts_with("-0b") {
-        let negative = format!("-{}", &v[3..]);
+    if let Some(rest) = v.strip_prefix("-0b") {
+        let negative = format!("-{}", rest);
         if let Ok(n) = i64::from_str_radix(&negative, 2) {
             return visitor.visit_i64(n);
         }

src/lib.rs

@@ -97,8 +97,6 @@
     // noisy
     clippy::missing_errors_doc,
     clippy::must_use_candidate,
-    // todo
-    clippy::manual_strip,
 )]
 
 pub use crate::de::{from_reader, from_slice, from_str, Deserializer};