ob-core: Remove LaTeX environment #+results type

* lisp/ob-core.el (org-babel-result-end): Alloow the result to end
into a LaTeX environment.

By adding latex-enviroment to the possible results types, a much
richer experience is possible for backends that can produce
LaTeX-formatted maths as their results (for example: Calc, Julia with
Latexify, Python with SymPy, Octave with symbolic). This is superior
to a LaTeX export block as LaTeX environments can be (1) rendered
inline, and (2) better used in non-LaTeX export formats (e.g. HTML
with MathJax).  Without this, backends can output a LaTeX environment,
but new results will be added in front instead of replacing the
environment.

lisp/ob-core.el

@@ -2559,8 +2559,9 @@ in the buffer."
 	 (let ((element (org-element-at-point)))
 	   (if (memq (org-element-type element)
 		     ;; Possible results types.
-		     '(drawer example-block export-block fixed-width item
-			      plain-list special-block src-block table))
+                     '(drawer example-block export-block fixed-width
+                              special-block src-block item plain-list table
+                              latex-environment))
 	       (save-excursion
 		 (goto-char (min (point-max) ;for narrowed buffers
 				 (org-element-property :end element)))