Rollup merge of rust-lang#143038 - Qelxiros:142676-private-dependency-traits, r=tgross35

avoid suggesting traits from private dependencies

fixes rust-lang#142676
fixes rust-lang#138191

r? ``@tgross35``

Author: jdonszelmann

rustc-std-workspace-core/Cargo.toml

@@ -1,3 +1,5 @@
+cargo-features = ["public-dependency"]
+
 [package]
 name = "rustc-std-workspace-core"
 version = "1.99.0"
@@ -11,5 +13,7 @@ edition = "2024"
 path = "lib.rs"
 
 [dependencies]
-core = { path = "../core" }
-compiler_builtins = { path = "../compiler-builtins/compiler-builtins", features = ["compiler-builtins"] }
+core = { path = "../core", public = true }
+compiler_builtins = { path = "../compiler-builtins/compiler-builtins", features = [
+  "compiler-builtins",
+] }