Fix amp-truncate-text docs. (#23205)
Fix amp-truncate-text docs. (#23205)

- Change backticks to code tag
- Fix old slot names
mhc-gh/amphtml,yandex-pcode/amphtml,danielrozenberg/amphtml,erwinmombay/amphtml,adup-tech/amphtml,media-net/amphtml,dotandads/amphtml,jmadler/amphtml,nexxtv/amphtml,jridgewell/amphtml,honeybadgerdontcare/amphtml,prateekbh/amphtml,taboola/amphtml,Gregable/amphtml,smartadserver/amphtml,src-code/amphtml,media-net/amphtml,yandex-pcode/amphtml,jpettitt/amphtml,adup-tech/amphtml,media-net/amphtml,jridgewell/amphtml,cory-work/amphtml,erwinmombay/amphtml,jpettitt/amphtml,zhangsu/amphtml,tlong2/amphtml,danielrozenberg/amphtml,rsimha-amp/amphtml,dotandads/amphtml,prateekbh/amphtml,tlong2/amphtml,jridgewell/amphtml,smartadserver/amphtml,honeybadgerdontcare/amphtml,jridgewell/amphtml,src-code/amphtml,jridgewell/amphtml,tlong2/amphtml,cory-work/amphtml,zhouyx/amphtml,smartadserver/amphtml,sharethrough/amphtml,adup-tech/amphtml,rsimha-amp/amphtml,zhouyx/amphtml,dotandads/amphtml,mhc-gh/amphtml,mhc-gh/amphtml,yandex-pcode/amphtml,voyagegroup/amphtml,erwinmombay/amphtml,erwinmombay/amphtml,honeybadgerdontcare/amphtml,cory-work/amphtml,jpettitt/amphtml,danielrozenberg/amphtml,alanorozco/amphtml,honeybadgerdontcare/amphtml,voyagegroup/amphtml,prateekbh/amphtml,zhangsu/amphtml,cory-work/amphtml,lannka/amphtml,smartadserver/amphtml,zhouyx/amphtml,erwinmombay/amphtml,zhangsu/amphtml,adup-tech/amphtml,erwinmombay/amphtml,alanorozco/amphtml,sharethrough/amphtml,alanorozco/amphtml,Gregable/amphtml,mhc-gh/amphtml,mhc-gh/amphtml,voyagegroup/amphtml,jpettitt/amphtml,rsimha-amp/amphtml,rsimha-amp/amphtml,tlong2/amphtml,media-net/amphtml,Gregable/amphtml,taboola/amphtml,jmadler/amphtml,src-code/amphtml,taboola/amphtml,lannka/amphtml,mhc-gh/amphtml,Gregable/amphtml,zhouyx/amphtml,rsimha-amp/amphtml,honeybadgerdontcare/amphtml,rsimha-amp/amphtml,zhangsu/amphtml,tlong2/amphtml,jmadler/amphtml,sharethrough/amphtml,zhouyx/amphtml,nexxtv/amphtml,voyagegroup/amphtml,sharethrough/amphtml,yandex-pcode/amphtml,nexxtv/amphtml,jridgewell/amphtml,yandex-pcode/amphtml,danielrozenberg/amphtml,alanorozco/amphtml,ampproject/amphtml,voyagegroup/amphtml,alanorozco/amphtml,danielrozenberg/amphtml,jpettitt/amphtml,Gregable/amphtml,danielrozenberg/amphtml,taboola/amphtml,jpettitt/amphtml,ampproject/amphtml,danielrozenberg/amphtml,lannka/amphtml,nexxtv/amphtml,Gregable/amphtml,ampproject/amphtml,honeybadgerdontcare/amphtml,media-net/amphtml,yandex-pcode/amphtml,tlong2/amphtml,voyagegroup/amphtml,cory-work/amphtml,media-net/amphtml,ampproject/amphtml,lannka/amphtml,nexxtv/amphtml,prateekbh/amphtml,smartadserver/amphtml,sharethrough/amphtml,media-net/amphtml,mhc-gh/amphtml,alanorozco/amphtml,adup-tech/amphtml,taboola/amphtml,media-net/amphtml,lannka/amphtml,alanorozco/amphtml,yandex-pcode/amphtml,zhouyx/amphtml,lannka/amphtml,ampproject/amphtml,prateekbh/amphtml,ampproject/amphtml,danielrozenberg/amphtml,rsimha-amp/amphtml,src-code/amphtml,jmadler/amphtml,dotandads/amphtml,Gregable/amphtml,voyagegroup/amphtml,taboola/amphtml,alanorozco/amphtml,taboola/amphtml,mhc-gh/amphtml,ampproject/amphtml,zhouyx/amphtml,jpettitt/amphtml,cory-work/amphtml,cory-work/amphtml,jpettitt/amphtml,Gregable/amphtml,zhangsu/amphtml,dotandads/amphtml,adup-tech/amphtml,dotandads/amphtml,jmadler/amphtml,src-code/amphtml,jmadler/amphtml,nexxtv/amphtml,smartadserver/amphtml,jridgewell/amphtml,zhangsu/amphtml,honeybadgerdontcare/amphtml,nexxtv/amphtml,ampproject/amphtml,src-code/amphtml,prateekbh/amphtml,lannka/amphtml,sharethrough/amphtml,prateekbh/amphtml