git_tutorial_1.rst: Fix grammatical errors
git_tutorial_1.rst: Fix grammatical errors

Fix a few grammatical errors in `git_tutorial_1.rst`
Fixes coala-analyser#1726

arush0311/coala,kartikeys98/coala,Uran198/coala,aptrishu/coala,scottbelden/coala,NalinG/coala,vinc456/coala,RJ722/coala,refeed/coala,impmihai/coala,yland/coala,coala/coala,rimacone/testing2,karansingh1559/coala,sagark123/coala,incorrectusername/coala,swatilodha/coala,kartikeys98/coala,MattAllmendinger/coala,netman92/coala,damngamerz/coala,d6e/coala,vinc456/coala,Shade5/coala,Balaji2198/coala,CruiseDevice/coala,mr-karan/coala,ManjiriBirajdar/coala,abhiroyg/coala,jayvdb/coala,arjunsinghy96/coala,nemaniarjun/coala,jayvdb/coala,karansingh1559/coala,yland/coala,Shade5/coala,ayushin78/coala,RJ722/coala,aptrishu/coala,tltuan/coala,JohnS-01/coala,arafsheikh/coala,JohnS-01/coala,SanketDG/coala,tushar-rishav/coala,karansingh1559/coala,Nosferatul/coala,rresol/coala,svsn2117/coala,shreyans800755/coala,arafsheikh/coala,yashLadha/coala,sils1297/coala,meetmangukiya/coala,sophiavanvalkenburg/coala,djkonro/coala,stevemontana1980/coala,lonewolf07/coala,MariosPanag/coala,nemaniarjun/coala,incorrectusername/coala,JohnS-01/coala,svsn2117/coala,AbdealiJK/coala,abhiroyg/coala,AbdealiJK/coala,saurabhiiit/coala,Asalle/coala,coala/coala,ayushin78/coala,saurabhiiit/coala,MattAllmendinger/coala,kartikeys98/coala,d6e/coala,Asnelchristian/coala,yashLadha/coala,lonewolf07/coala,refeed/coala,mr-karan/coala,stevemontana1980/coala,NalinG/coala,scottbelden/coala,arjunsinghy96/coala,vinc456/coala,MattAllmendinger/coala,arush0311/coala,lonewolf07/coala,sagark123/coala,tltuan/coala,MariosPanag/coala,swatilodha/coala,yashLadha/coala,dagdaggo/coala,CruiseDevice/coala,rresol/coala,NiklasMM/coala,NiklasMM/coala,meetmangukiya/coala,impmihai/coala,yashtrivedi96/coala,dagdaggo/coala,Asnelchristian/coala,Asalle/coala,arjunsinghy96/coala,swatilodha/coala,arafsheikh/coala,abhiroyg/coala,yashtrivedi96/coala,meetmangukiya/coala,dagdaggo/coala,shreyans800755/coala,yland/coala,MariosPanag/coala,coala-analyzer/coala,tltuan/coala,NalinG/coala,sophiavanvalkenburg/coala,nemaniarjun/coala,saurabhiiit/coala,tushar-rishav/coala,incorrectusername/coala,netman92/coala,sils1297/coala,tushar-rishav/coala,netman92/coala,RJ722/coala,Shade5/coala,NalinG/coala,Asalle/coala,Balaji2198/coala,CruiseDevice/coala,damngamerz/coala,refeed/coala,AbdealiJK/coala,aptrishu/coala,coala-analyzer/coala,rresol/coala,stevemontana1980/coala,rimacone/testing2,SanketDG/coala,rimacone/testing2,SanketDG/coala,coala-analyzer/coala,ManjiriBirajdar/coala,NalinG/coala,NalinG/coala,ManjiriBirajdar/coala,Uran198/coala,NiklasMM/coala,scottbelden/coala,d6e/coala,jayvdb/coala,djkonro/coala,Nosferatul/coala,arush0311/coala,ayushin78/coala,sagark123/coala,svsn2117/coala,Balaji2198/coala,sils1297/coala,Nosferatul/coala,coala/coala,damngamerz/coala,impmihai/coala,djkonro/coala,yashtrivedi96/coala,Asnelchristian/coala,Uran198/coala,sophiavanvalkenburg/coala,mr-karan/coala,NalinG/coala,shreyans800755/coala