ob-R, ob-python, ob-shell: Fix async indicator regexps

* lisp/ob-R.el (ob-session-async-org-babel-R-evaluate-session):
* lisp/ob-python.el (org-babel-python-async-evaluate-session):
* lisp/ob-shell.el (org-babel-sh-evaluate): Make regexps stricter,
matching exactly for what we put there.  Previous regexps were not
always matching file names with underscores.

Reported-by: Sam Crawford <sam@crawf.uk>
Link: https://orgmode.org/list/h6c_ta-utc-ugGl4Bq1XXJpXcpXlm_rblFIGJKMH0xiPc-NnJsuVe2z8atXGNcsBlJiR9c24bqLyXFX3GO0tiWtyTUzXMJA81wRIIB-DQfo=@crawf.uk

lisp/ob-R.el

@@ -484,7 +484,7 @@ Returns a placeholder string for insertion, to later be replaced
 by `org-babel-comint-async-filter'."
   (org-babel-comint-async-register
    session (current-buffer)
-   "^\\(?:[>.+] \\)*\\[1\\] \"ob_comint_async_R_\\(.+?\\)_\\(.+\\)\"$"
+   "^\\(?:[>.+] \\)*\\[1\\] \"ob_comint_async_R_\\(start\\|end\\|file\\)_\\(.+\\)\"$"
    'org-babel-chomp
    'ob-session-async-R-value-callback)
   (cl-case result-type

lisp/ob-python.el

@@ -537,7 +537,7 @@ Returns a placeholder string for insertion, to later be replaced
 by `org-babel-comint-async-filter'."
   (org-babel-comint-async-register
    session (current-buffer)
-   "ob_comint_async_python_\\(.+\\)_\\(.+\\)"
+   "ob_comint_async_python_\\(start\\|end\\|file\\)_\\(.+\\)"
    'org-babel-chomp 'org-babel-python-async-value-callback)
   (pcase result-type
     (`output

lisp/ob-shell.el

@@ -338,7 +338,7 @@ return the value of the last statement in BODY."
                     (org-babel-comint-async-register
                      session
                      (current-buffer)
-                     "ob_comint_async_shell_\\(.+\\)_\\(.+\\)"
+                     "ob_comint_async_shell_\\(start\\|end\\|file\\)_\\(.+\\)"
                      'ob-shell-async-chunk-callback
                      nil)
                     (org-babel-comint-async-delete-dangling-and-eval