Add hanging signs to the sign category

[TheLimeGlass]

any oak sign should reflect any sign regardless of it's placement, as long as it's an oak sign, it will fall under the oak sign category.

[Moderocky]

This looks like it just adds the changes that were rejected in #88

[TheLimeGlass]

Damn that's crazy SkriptLang/Skript#6220

[sovdeeth]

The issue with this is that "oak sign" shouldn't include hanging oak signs, in my opinion. "Any oak sign" should, though, for comparison.
It'd be pretty simple to split the two up.

[Moderocky]

Damn that's crazy SkriptLang/Skript#6220

Your PR does not address this issue at all.
The issue you have linked is about warped and crimson (the pink and blue nether wood types) hanging signs not being included in the signs alias, and cherry and bamboo regular signs not being included in the alias.
This PR doesn't add either of these missing things to the alias, it adds the hanging signs to the regular signs alias.