Spoiler tag conversion (markdown -> nexus bbc)

Thanks again for the fantastic tool :) Something which can be improved (with regard to the markdown to nexus bbc conversion):

[workflow used](https://github.com/jpw1991/chebs-necromancy/actions/runs/5944963059)

## HTML Spoiler

The html spoiler section doesn't get carried over correctly:

### Markdown


```md

2023

Date | Version | Notes
--- | --- | ---
23/08/2023 | 4.2.0 | update for new valheim patch
02/08/2023 | 4.1.1 | strengthen null checks in Phylactery patch
30/07/2023 | 4.1.0 | add phylactery that consumes dragon eggs when you die and teleports you back to its location
28/07/2023 | 4.0.0 | Workers should behave more realistically with gradual destruction of rocks, trees, etc.
23/07/2023 | 3.7.1 | Fix problem where the minion state wasn't getting localized in the hover text
22/07/2023 | 3.7.0 | Remove configurable Neckro Gatherer container size because containers have not been configurable since 3.3.1 (it resulted in a bug - see issue 100 on GitHub); add Russian translation
21/07/2023 | 3.6.2 | fix bug where onePerPlayer was set to true for character drops, which would result in incorrect resource amounts getting refunded
20/07/2023 | 3.6.1 | Add config option to make draugr quiet; update CVL to 2.1.1
13/07/2023 | 3.6.0 | Try to make workers behave better; update CVL to 2.1.0 to prepare for upcoming changes
21/06/2023 | 3.5.2 | Treasure pylon checks that Piece is not null before processing container
16/06/2023 | 3.5.1 | Option to toggle smoke effects off wraiths (some players getting blinded out here)
12/06/2023 | 3.5.0 | Update for new Valheim version
24/05/2023 | 3.3.2 | Functions created in 3.3.0 moved into Cheb's Valheim Library for Cheb's Mercenaries
24/05/2023 | 3.3.1 | Come up with a solution for issue 100 by removing ability to set custom container sizes.
```

### BBC


```bbc
[spoiler]
[b]2023[/b]
[/spoiler]
Date | Version | Notes --- | --- | --- 23/08/2023 | 4.2.0 | update for new valheim patch 02/08/2023 | 4.1.1 | strengthen null checks in Phylactery patch 30/07/2023 | 4.1.0 | add phylactery that consumes dragon eggs when you die and teleports you back to its location 28/07/2023 | 4.0.0 | Workers should behave more realistically with gradual destruction of rocks, trees, etc. 23/07/2023 | 3.7.1 | Fix problem where the minion state wasn't getting localized in the hover text 22/07/2023 | 3.7.0 | Remove configurable Neckro Gatherer container size because containers have not been configurable since 3.3.1 (it resulted in a bug - see issue 100 on GitHub); add Russian translation 21/07/2023 | 3.6.2 | fix bug where onePerPlayer was set to true for character drops, which would result in incorrect resource amounts getting refunded 20/07/2023 | 3.6.1 | Add config option to make draugr quiet; update CVL to 2.1.1 13/07/2023 | 3.6.0 | Try to make workers behave better; update CVL to 2.1.0 to prepare for upcoming changes 21/06/2023 | 3.5.2 | Treasure pylon checks that Piece is not null before processing container 16/06/2023 | 3.5.1 | Option to toggle smoke effects off wraiths (some players getting blinded out here) 12/06/2023 | 3.5.0 | Update for new Valheim version 24/05/2023 | 3.3.2 | Functions created in 3.3.0 moved into Cheb's Valheim Library for Cheb's Mercenaries 24/05/2023 | 3.3.1 | Come up with a solution for issue 100 by removing ability to set custom container sizes. 18/05/2023 | 3.2.3 | Extra safe-guarding against null objects on m_piece and GetInventory when Neckro Gatherer is attempting to find containers. These things shouldn't ever be null as far as I understand - but other mods can do wild things apparently. 16/05/2023 | 3.3.0 | Make Orb behave like modern wands; Permit alternative materials for minion making via piping 12/05/2023 | 3.2.2 | Configurable item cost for Neckro Gatherers 11/05/2023 | 3.2.1 | Unbundle DLL to fix bug of wands not working; ignore collision with carts 02/05/2023 | 3.2.0 | Commandable workers; If a woodcutter is swinging, but missing, the damage gets dealt anyway; remove tooltier stuff for simplicity and streamlining. People can use 3rd party item-alteration mods instea
```

No files or tests are named. Start by reproducing the Markdown-to-Nexus BBCode conversion with the supplied example, then inspect the conversion entry point for HTML spoilers and tables; done when the spoiler preserves its heading and the table content remains correctly structured inside it.

Written by the indexing model from the issue text.