docs(installation): remove original sentence
docs(installation): remove original sentence

RxJS-CN/RxJS-Docs-CN,SangKa/RxJS-Docs-CN,RxJS-CN/RxJS-Docs-CN,RxJS-CN/RxJS-Docs-CN,SangKa/RxJS-Docs-CN,RxJS-CN/RxJS-Docs-CN,SangKa/RxJS-Docs-CN,SangKa/RxJS-Docs-CN