Adds Common Second Language quirk, tweaks to partial understanding (#90614)

## About The Pull Request

- Tweaks partial understanding. 

Paragraphs are now split into sentences first creating more natural
breaks between sentences.

- Adds "Common Second Language" quirk

This quirk changes your default understanding of common (up to) 90%
(your choice), meaning you drop the occasional word.


![image](https://github.com/user-attachments/assets/63e9d67b-7db2-4d23-9d0f-bae175962db4)


![image](https://github.com/user-attachments/assets/840ef391-5126-4ba7-9298-804686bcd6df)

Additionally, when your sanity drops below a threshold, you become
forced to speak your native language, albeit with a partial
understanding applied for everyone else.

Incompatible with similar language quirks + can't be taken by humans
(yet?)

## Why It's Good For The Game

Just a fun way to play around with the new "partial understanding"
system.

## Changelog

🆑 Melbert
add: "Common Second Language" quirk
qol: Language translations chunk sentences together better, making
partial understanding a bit easier to parse.
/🆑

code/controllers/subsystem/processing/quirks.dm

@@ -23,7 +23,7 @@ GLOBAL_LIST_INIT_TYPED(quirk_blacklist, /list/datum/quirk, list(
 	list(/datum/quirk/social_anxiety, /datum/quirk/mute),
 	list(/datum/quirk/mute, /datum/quirk/softspoken),
 	list(/datum/quirk/poor_aim, /datum/quirk/bighands),
-	list(/datum/quirk/bilingual, /datum/quirk/foreigner),
+	list(/datum/quirk/bilingual, /datum/quirk/foreigner, /datum/quirk/csl),
 	list(/datum/quirk/spacer_born, /datum/quirk/item_quirk/settler),
 	list(/datum/quirk/photophobia, /datum/quirk/nyctophobia),
 	list(/datum/quirk/item_quirk/settler, /datum/quirk/freerunning),