Merge pull request #63 from polarathene/patch-2

docs: `Cargo.toml` - Revise description of `core` dep

Author: alexcrichton

Cargo.toml

@@ -29,10 +29,10 @@ doctest = false
 libc = { version = "0.2", default-features = false }
 
 [dependencies]
-# For more information on these dependencies see rust-lang/rust's
-# `src/tools/rustc-std-workspace` folder
-core = { version = '1.0.0', optional = true, package = 'rustc-std-workspace-core' }
 cfg-if = "1.0"
+# This is an internal dep for supporting the nightly toolchain option `-Z build-std`:
+# https://github.com/rust-lang/rust/blob/main/library/rustc-std-workspace-core/README.md
+core = { version = '1.0.0', optional = true, package = 'rustc-std-workspace-core' }
 
 [target.'cfg(target_os = "windows")'.dependencies.windows-sys]
 version = ">=0.52.0, <=0.61.*"