Update strings.js
Update strings.js

add some missing Chinese translation
pcottle/learnGitBranching,pcottle/learnGitBranching,andriymoroz/learnGitBranching,pcottle/learnGitBranching,andriymoroz/learnGitBranching,edombowsky/learnGitBranching,Maximaximum/learnGitBranching,edombowsky/learnGitBranching,Maximaximum/learnGitBranching