Punctuation and grammar correction in docs/docs/associations.md.  (#7211)
Punctuation and grammar correction in docs/docs/associations.md.  (#7211)

* (docs/docs/associations.md) punctuation fix - added comma

* (docs/docs/associations.md) punctuation fix - added comma

* (docs/docs/associations.md) grammar correction

grimurd/sequelize,Alexsey/sequelize,pola88/sequelize,gorangajic/sequelize,darwinserrano/sequelize,overlookmotel/sequelize,Verdier/sequelize,overlookmotel/sequelize,Americas/sequelize,cbauerme/sequelize,yjwong/sequelize,konnecteam/sequelize,sequelize/sequelize,nemisj/sequelize,majorleaguesoccer/sequelize,Wsiegenthaler/sequelize,sequelize/sequelize,PhinCo/sequelize,jayprakash1/sequelize,inDream/sequelize,p0vidl0/sequelize,sequelize/sequelize,jayprakash1/sequelize,gintsgints/sequelize,Americas/sequelize,inDream/sequelize,seshness/sequelize,mikeringrose/sequelize,PsiXdev/sequelize,StefanoDalpiaz/sequelize,konnecteam/sequelize,yonjah/sequelize