gnu: Remove rust-kstring-1.

* gnu/packages/crates-io.scm (rust-kstring-1): Delete variable.

gnu/packages/crates-io.scm

@@ -31522,32 +31522,6 @@ kernel32.")
     (description "Key String provides a Rust package optimized for map keys.")
     (license (list license:expat license:asl2.0))))
 
-(define-public rust-kstring-1
-  (package
-    (name "rust-kstring")
-    (version "1.1.0")
-    (source
-      (origin
-        (method url-fetch)
-        (uri (crate-uri "kstring" version))
-        (file-name (string-append name "-" version ".tar.gz"))
-        (sha256
-         (base32 "1r4n9fa5scikqvl736nxghcfa6s3b07xz61w43hyzs2qb3wmd3nk"))))
-    (build-system cargo-build-system)
-    (arguments
-     `(#:skip-build? #t     ; Uses unstable features.
-       #:cargo-inputs
-       (("rust-document-features" ,rust-document-features-0.2)
-        ("rust-serde" ,rust-serde-1)
-        ("rust-static-assertions" ,rust-static-assertions-1))
-       #:cargo-development-inputs
-       (("rust-criterion" ,rust-criterion-0.3)
-        ("rust-proptest" ,rust-proptest-1))))
-    (home-page "https://github.com/cobalt-org/kstring")
-    (synopsis "String optimized for map keys")
-    (description "Key String provides a Rust package optimized for map keys.")
-    (license (list license:expat license:asl2.0))))
-
 (define-public rust-kv-log-macro-1
   (package
     (name "rust-kv-log-macro")