Bulk client regen - builder documentation and Generated annotation

[chingor13]

Combining multiple, similar PRs into a single PR:

• Regenerate asset client (Regenerate asset client #5817)
• Regenerate bigquerystorage client (Regenerate bigquerystorage client #5819)
• Regenerate bigtable client (Regenerate bigtable client #5820)
• Regenerate compute client (Regenerate compute client #5821)
• Regenerate container client (Regenerate container client #5822)
• Regenerate containeranalysis client (Regenerate containeranalysis client #5823)
• Regenerate dataproc client (Regenerate dataproc client #5825)
• Regenerate dlp client (Regenerate dlp client #5826)
• Regenerate errorreporting client (Regenerate errorreporting client #5827)
• Regenerate firestore client (Regenerate firestore client #5828)
• Regenerate iamcredentials client (Regenerate iamcredentials client #5829)
• Regenerate iot client (Regenerate iot client #5830)
• Regenerate kms client (Regenerate kms client #5831)
• Regenerate language client (Regenerate language client #5832)
• Regenerate logging client (Regenerate logging client #5833)
• Regenerate monitoring client (Regenerate monitoring client #5834)
• Regenerate os-login client (Regenerate os-login client #5835)
• Regenerate phishingprotection client (Regenerate phishingprotection client #5836)
• Regenerate pubsub client (Regenerate pubsub client #5837)
• Regenerate recaptchaenterprise client (Regenerate recaptchaenterprise client #5838)
• Regenerate scheduler client (Regenerate scheduler client #5839)
• Regenerate talent client (Regenerate talent client #5840)
• Regenerate tasks client (Regenerate tasks client #5841)
• Regenerate texttospeech client (Regenerate texttospeech client #5842)
• Regenerate trace client (Regenerate trace client #5843)
• Regenerate webrisk client (Regenerate webrisk client #5844)
• Regenerate websecurityscanner client (Regenerate websecurityscanner client #5845)
• Regenerate grafeas client (Regenerate grafeas client #5846)

[BenWhitehead]

Kokoro - Integration: Firestore is failing with the same flakey test identified previously. Feel free to proceed with merging.