gnu: Rename "qtoctave" to "octave".

* gnu/packages/maths.scm (qtoctave): Define in terms of 'deprectated-package'.
(octave): New variable, formerly known as "qtoctave".

gnu/packages/maths.scm

@@ -1497,9 +1497,9 @@ Work may be performed both at the interactive command-line as well as via
 script files.")
     (license license:gpl3+)))
 
-(define-public qtoctave
+(define-public octave
   (package (inherit octave-cli)
-    (name "qtoctave")
+    (name "octave")
     (source (origin
               (inherit (package-source octave-cli))))
     (inputs
@@ -1525,6 +1525,9 @@ script files.")
                   "qscintilla2_qt5"))
                #t))))))))
 
+(define-public qtoctave
+  (deprecated-package "qtoctave" octave))
+
 (define-public opencascade-oce
   (package
     (name "opencascade-oce")