pgAdmin 4 commit: 1) Fix accessibility issue for checkbox in IE11. Fixe

1) Fix accessibility issue for checkbox in IE11. Fixes #4490
2) Fix adjacent switch cell focus issue in backgrid for IE.

Branch
------
master

Details
-------
https://git.postgresql.org/gitweb?p=pgadmin4.git;a=commitdiff;h=136bb412a1363a161a7b4f37151d97db1de19cfb
Author: Ganesh Jaybhay <ganesh.jaybhay@enterprisedb.com>

Modified Files
--------------
docs/en_US/release_notes.rst                |  1 +
docs/en_US/release_notes_4_12.rst           | 20 ++++++++++++++++++++
web/pgadmin/static/js/backgrid.pgadmin.js   | 14 +++++++++-----
web/pgadmin/static/scss/_pgadmin.style.scss |  2 +-
4 files changed, 31 insertions(+), 6 deletions(-)