TANGO: Adding insert index and symbol icons and fixing others

Change-Id: Ibaca345f20baee3ddb5f76cd8079d8a34157eabb
Reviewed-on: https://gerrit.libreoffice.org/12259
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Tested-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>