Vim 给段落增加递增编号 Add increment orde

有文本：

Siem Reap(REP) - Hang Zhou(HGH) - Cambodia Angkor Airlines
Siem Reap(REP) - Shang Hai(PVG) - Cambodia Angkor Airlines

Siem Reap(REP) - Kun Ming(KMG) - China Eastern
Siem Reap(REP) - Shang Hai(PVG) - China Eastern
Siem Reap(REP) - Guang Zhou(CAN) - China Southern

Siem Reap(REP) - Hei Fei(HFE) - JC International
Siem Reap(REP) - Hong Kong(HKG) - Hong Kong Express
Siem Reap(REP) - Jing Hong(JHG) - JC International
Siem Reap(REP) - Wan Zhou(WXN) - JC International
Siem Reap(REP) - Xi'an(XIY) - JC International

Siem Reap(REP) - Chang Sha(CSX) - Lanmei Airlines
Siem Reap(REP) - Cheng Du(CTU) - Lanmei Airlines
Siem Reap(REP) - Dun Huang(DNH) - Lanmei Airlines
Siem Reap(REP) - En Shi(ENH) - Lanmei Airlines
Siem Reap(REP) - Nan Jing(KHN) - Lanmei Airlines 
Siem Reap(REP) - Shen Zhen(SZX) - Lanmei Airlines
Siem Reap(REP) - Shi Jia Zhuang(SJW) - Lanmei Airlines
Siem Reap(REP) - Tian Jin(TSN) - Lanmei Airlines
Siem Reap(REP) - Wu Han(WUH) - Lanmei Airlines
Siem Reap(REP) - Xu Zhou(XUZ) - Lanmei Airlines
Siem Reap(REP) - Zun Yi(ZYI) - Lanmei Airlines

Siem Reap(REP) - Nan Ning(NNG) - Qingdao Airlines
Siem Reap(REP) - Lan Zhou(LHW) - Qingdao Airlines

Siem Reap(REP) - Chong Qing(CKG) - Shandong Airlines

Siem Reap(REP) - Bei Jing(PEK) - Sky Angkor Airlines
Siem Reap(REP) - Nan Chang(KHN) - Sky Angkor Airlines
Siem Reap(REP) - Nan Jing(KHN) - Sky Angkor Airlines
Siem Reap(REP) - Ning Bo(NGB) - Sky Angkor Airlines

Siem Reap(REP) - Xia Men(XMN) - Xiamen Airlines

Siem Reap(REP) - Hong Kong(HKG) - Cathay Dragon

需要得到如下效果：

1. Siem Reap(REP) - Hang Zhou(HGH) - Cambodia Angkor Airlines
2. Siem Reap(REP) - Shang Hai(PVG) - Cambodia Angkor Airlines

1. Siem Reap(REP) - Kun Ming(KMG) - China Eastern
2. Siem Reap(REP) - Shang Hai(PVG) - China Eastern
3. Siem Reap(REP) - Guang Zhou(CAN) - China Southern

1. Siem Reap(REP) - Hei Fei(HFE) - JC International
2. Siem Reap(REP) - Hong Kong(HKG) - Hong Kong Express
3. Siem Reap(REP) - Jing Hong(JHG) - JC International
4. Siem Reap(REP) - Wan Zhou(WXN) - JC International
5. Siem Reap(REP) - Xi'an(XIY) - JC International

1. Siem Reap(REP) - Chang Sha(CSX) - Lanmei Airlines
2. Siem Reap(REP) - Cheng Du(CTU) - Lanmei Airlines
3. Siem Reap(REP) - Dun Huang(DNH) - Lanmei Airlines
4. Siem Reap(REP) - En Shi(ENH) - Lanmei Airlines
5. Siem Reap(REP) - Nan Jing(KHN) - Lanmei Airlines 
6. Siem Reap(REP) - Shen Zhen(SZX) - Lanmei Airlines
7. Siem Reap(REP) - Shi Jia Zhuang(SJW) - Lanmei Airlines
8. Siem Reap(REP) - Tian Jin(TSN) - Lanmei Airlines
9. Siem Reap(REP) - Wu Han(WUH) - Lanmei Airlines
10. Siem Reap(REP) - Xu Zhou(XUZ) - Lanmei Airlines
11. Siem Reap(REP) - Zun Yi(ZYI) - Lanmei Airlines

1. Siem Reap(REP) - Nan Ning(NNG) - Qingdao Airlines
2. Siem Reap(REP) - Lan Zhou(LHW) - Qingdao Airlines

1. Siem Reap(REP) - Chong Qing(CKG) - Shandong Airlines

1. Siem Reap(REP) - Bei Jing(PEK) - Sky Angkor Airlines
2. Siem Reap(REP) - Nan Chang(KHN) - Sky Angkor Airlines
3. Siem Reap(REP) - Nan Jing(KHN) - Sky Angkor Airlines
4. Siem Reap(REP) - Ning Bo(NGB) - Sky Angkor Airlines

1. Siem Reap(REP) - Xia Men(XMN) - Xiamen Airlines

1. Siem Reap(REP) - Hong Kong(HKG) - Cathay Dragon

命令如下：

let i=1 | g//if(getline('.') != '') | s/^/\=i.'. '/ | let i+=1 | else if(get line('.') == '') | let i=1 | endif 

运行之前，gg 回到文章初始位置。