gnu: oil-shell: Rename to "oil".

* gnu/packages/shells.scm (oil): Rename variable from…
(oil-shell): …this.  Redefine using DEPRECATED-PACKAGE.

Signed-off-by: Tobias Geerinckx-Rice <me@tobias.gr>

gnu/packages/shells.scm

@@ -780,9 +780,9 @@ (define-public mksh
     (license (list miros
                    isc))))              ; strlcpy.c
 
-(define-public oil-shell
+(define-public oil
   (package
-    (name "oil-shell")
+    (name "oil")
     (version "0.7.0")
     (source (origin
               (method url-fetch)
@@ -826,6 +826,9 @@ (define-public oil-shell
     (license (list psfl ; The Oil sources include a patched Python 2 source tree
                    asl2.0))))
 
+(define-public oil-shell
+  (deprecated-package "oil-shell" oil))
+
 (define-public gash
   (package
     (name "gash")