Bugfix/remove custom html

[StaticRocket]

Remove a bunch of custom html blocks that either weren't changing the document output or were directly conflicting with built in directives.

[github-actions]

New warnings found with rstcheck:

source/linux/Industrial_Protocols/_RSTP_with_Switch_Firmware.rst:53: (INFO/1) Enumerated list start value not ordinal-1: "3" (ordinal 3)
source/linux/Industrial_Protocols/_RSTP_with_Switch_Firmware.rst:114: (INFO/1) Enumerated list start value not ordinal-1: "4" (ordinal 4)
source/linux/Industrial_Protocols/_RSTP_with_Switch_Firmware.rst:151: (INFO/1) Enumerated list start value not ordinal-1: "5" (ordinal 5)
source/linux/Industrial_Protocols/PTP/_PTP.rst:1613: (INFO/1) Duplicate implicit target name: "limitations".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1642: (INFO/1) Duplicate implicit target name: "overview".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1669: (INFO/1) Duplicate implicit target name: "hardware".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1675: (INFO/1) Duplicate implicit target name: "software".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1771: (INFO/1) Duplicate implicit target name: "test setup/procedure".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1800: (ERROR/3) Error in "code-block" directive:
source/linux/Industrial_Protocols/PTP/_PTP.rst:1952: (INFO/1) Duplicate implicit target name: "procedure".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1963: (INFO/1) Duplicate implicit target name: "test results".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1966: (INFO/1) Duplicate implicit target name: "test 1. with a hybrid clock (oc+tc) between master and slave clock".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1971: (INFO/1) Duplicate implicit target name: "test 2. without a hybrid clock between master and slave clock".
source/linux/Industrial_Protocols/PTP/_PTP.rst:1976: (INFO/1) Duplicate implicit target name: "limitations".