Upgrade to rust toolchain 1.86 (#6134)

rust/kcl-lib/src/docs/gen_std_tests.rs

@@ -242,7 +242,7 @@ fn init_handlebars() -> Result<handlebars::Handlebars<'static>> {
              out: &mut dyn handlebars::Output|
              -> handlebars::HelperResult {
                 let param = h.param(0).and_then(|v| v.value().as_str()).unwrap_or("");
-                let basename = param.split('/').last().unwrap_or("");
+                let basename = param.split('/').next_back().unwrap_or("");
                 out.write(&format!("`{}`", basename))?;
                 Ok(())
             },

rust/kcl-lib/src/docs/mod.rs

@@ -612,7 +612,7 @@ pub fn get_description_string_from_schema(schema: &schemars::schema::RootSchema)
     }
 
     if let Some(reference) = &schema.schema.reference {
-        if let Some(definition) = schema.definitions.get(reference.split('/').last().unwrap_or("")) {
+        if let Some(definition) = schema.definitions.get(reference.split('/').next_back().unwrap_or("")) {
             let schemars::schema::Schema::Object(definition) = definition else {
                 return None;
             };

rust/kcl-lib/src/lsp/kcl/mod.rs

@@ -1194,7 +1194,7 @@ impl LanguageServer for Backend {
                 // Get last word
                 let last_word = line_prefix
                     .split(|c: char| c.is_whitespace() || c.is_ascii_punctuation())
-                    .last()
+                    .next_back()
                     .unwrap_or("");
 
                 // If the last word starts with a digit, return no completions

rust/rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.85"
+channel = "1.86"
 components = ["clippy", "rustfmt"]