doc/webp-container-spec: light cosmetics
doc/webp-container-spec: light cosmetics

- provide anchor links to the bitstream chunks referenced in the
  extended format section
- remove some unnecessary parenthetical notation and add some
  consistency to various chunk element definitions

Change-Id: Ifd946fee81b36e4e555399555a2a58c853fdc3b7

comoyo/gonzo-libwebp,ya7lelkom/libwebp,iniwf/webm.libwebp,iniwf/webm.libwebp,appunite/libwebp,dumganhar/libwebp,comoyo/gonzo-libwebp,matanbs/webm.libwebp,Suvarna1488/webm.libwebp,reimaginemedia/webm.libwebp,Suvarna1488/webm.libwebp,abwiz0086/webm.libwebp,reimaginemedia/webm.libwebp,redengineer/libwebp,imazen/libwebp,Aexyn/libwebp,webmproject/libwebp,ericmckean/webm.libwebp,comoyo/gonzo-libwebp,yohunl/libwebp,jiehu5114/libwebp,webmproject/libwebp,kim42083/webm.libwebp,zofuthan/libwebp,PKRoma/libwebp,redengineer/libwebp,redengineer/libwebp,Acidburn0zzz/webm.libwebp,cysp/libwebp,jacklicn/libwebp,PKRoma/libwebp,yohunl/libwebp,Acidburn0zzz/webm.libwebp,kleopatra999/webm.libwebp,appunite/libwebp,rxl194/libwebp,matanbs/webm.libwebp,gshORTON/webm.libwebp,jacklicn/libwebp,abwiz0086/webm.libwebp,Suvarna1488/webm.libwebp,appunite/libwebp,Suvarna1488/webm.libwebp,rxl194/libwebp,comoyo/gonzo-libwebp,gshORTON/webm.libwebp,ya7lelkom/libwebp,ttyangf/libwebp,zofuthan/libwebp,cysp/libwebp,matanbs/webm.libwebp,abwiz0086/webm.libwebp,keane83/BLE_IM,rxl194/libwebp,matanbs/webm.libwebp,kleopatra999/webm.libwebp,yohunl/libwebp,Maria1099/webm.libwebp,Tekserve/libwebp,reimaginemedia/webm.libwebp,altogother/webm.libwebp,PKRoma/libwebp,webmproject/libwebp,ya7lelkom/libwebp,Aexyn/libwebp,Maria1099/webm.libwebp,kalli123/webm.libwebp,kim42083/webm.libwebp,imazen/libwebp,ericmckean/webm.libwebp,jacklicn/libwebp,appunite/libwebp,comoyo/gonzo-libwebp,matanbs/webm.libwebp,kalli123/webm.libwebp,ericmckean/webm.libwebp,Acidburn0zzz/webm.libwebp,iniwf/webm.libwebp,altogother/webm.libwebp,kim42083/webm.libwebp,Tekserve/libwebp,altogother/webm.libwebp,gshORTON/webm.libwebp,altogother/webm.libwebp,rxl194/libwebp,jiehu5114/libwebp,redengineer/libwebp,Aexyn/libwebp,reimaginemedia/webm.libwebp,Maria1099/webm.libwebp,keane83/BLE_IM,Maria1099/webm.libwebp,dumganhar/libwebp,Distrotech/libwebp,ttyangf/libwebp,comoyo/gonzo-libwebp,zofuthan/libwebp,kalli123/webm.libwebp,rxl194/libwebp,zofuthan/libwebp,webmproject/libwebp,ttyangf/libwebp,Aexyn/libwebp,imazen/libwebp,Distrotech/libwebp,PKRoma/libwebp,abwiz0086/webm.libwebp,kleopatra999/webm.libwebp,jiehu5114/libwebp,altogother/webm.libwebp,reimaginemedia/webm.libwebp,ya7lelkom/libwebp,jiehu5114/libwebp,Suvarna1488/webm.libwebp,imazen/libwebp,iniwf/webm.libwebp,cysp/libwebp,gshORTON/webm.libwebp,ttyangf/libwebp,keane83/BLE_IM,kleopatra999/webm.libwebp,yohunl/libwebp,keane83/BLE_IM,gshORTON/webm.libwebp,Aexyn/libwebp,Tekserve/libwebp,Tekserve/libwebp,Acidburn0zzz/webm.libwebp,webmproject/libwebp,iniwf/webm.libwebp,jacklicn/libwebp,ericmckean/webm.libwebp,yohunl/libwebp,redengineer/libwebp,PKRoma/libwebp,PKRoma/libwebp,kleopatra999/webm.libwebp,kalli123/webm.libwebp,jacklicn/libwebp,dumganhar/libwebp,keane83/BLE_IM,appunite/libwebp,cysp/libwebp,kalli123/webm.libwebp,ericmckean/webm.libwebp,ttyangf/libwebp,abwiz0086/webm.libwebp,zofuthan/libwebp,jiehu5114/libwebp,Distrotech/libwebp,imazen/libwebp,kim42083/webm.libwebp,comoyo/gonzo-libwebp,appunite/libwebp,Acidburn0zzz/webm.libwebp,ya7lelkom/libwebp,kim42083/webm.libwebp,Maria1099/webm.libwebp