Update code switching prompts and reorganize U3Pro docs

fern/pages/speech-to-text/pre-recorded-audio/prompt-engineering.mdx

@@ -70,7 +70,7 @@ Always: Transcribe speech with your best guess based on context in all possible
 
 This gives the model clear guidance to always attempt transcription while keeping instructions minimal. It's a great starting point for most use cases.
 
-### Verbatim with multilingual support
+### Verbatim with code-switching/multilingual support
 
 If you need maximum verbatim capture and multilingual code-switching support, use this prompt:
 
@@ -204,6 +204,18 @@ Do you and Quentin still socialize, uh, when you come to Los Angeles, or is it l
 
 **Example prompts:**
 
+```text
+Required: Preserve the original language(s) and script as spoken,
+including code-switching and mixed-language phrases.
+
+Mandatory: Preserve linguistic speech patterns including disfluencies,
+filler words, hesitations, repetitions, stutters, false starts, and
+colloquialisms in the spoken language.
+
+Always: Transcribe speech with your best guess based on context in all
+possible scenarios where speech is present in the audio.
+```
+
 ```text
 Include spoken filler words like "um," "uh," "you know," "like," plus repetitions
 and false starts when clearly spoken.
@@ -526,12 +538,15 @@ For production use cases requiring consistent speaker labels, use the speaker di
 **Example prompts:**
 
 ```text
-Transcribe in the original language mix (code-switching), preserving words
-in the language they are spoken.
-```
+Required: Preserve the original language(s) and script as spoken,
+including code-switching and mixed-language phrases.
 
-```text
-Preserve natural code-switching between English and Spanish. Retain spoken language as-is with mixed language words.
+Mandatory: Preserve linguistic speech patterns including disfluencies,
+filler words, hesitations, repetitions, stutters, false starts, and
+colloquialisms in the spoken language.
+
+Always: Transcribe speech with your best guess based on context in all
+possible scenarios where speech is present in the audio.
 ```
 
 <Warning>