Adjust prefer_core config documentation

Author: Veykril

crates/rust-analyzer/src/config.rs

@@ -262,7 +262,7 @@ config_data! {
         imports_group_enable: bool                           = "true",
         /// Whether to allow import insertion to merge new imports into single path glob imports like `use std::fmt::*;`.
         imports_merge_glob: bool           = "true",
-        /// Prefer to use imports of the core crate over the std crate.
+        /// Prefer to use imports of the core crate, then alloc and finally std crate.
         imports_prefer_core: bool                     = "false",
         /// The path structure for newly inserted paths to use.
         imports_prefix: ImportPrefixDef               = "\"plain\"",