add guidance on adding copyright and license header to new source files (#6140)
add guidance on adding copyright and license header to new source files (#6140)


daxian-dbw/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,JamesWTruher/PowerShell-1,JamesWTruher/PowerShell-1,TravisEz13/PowerShell,PaulHigin/PowerShell,PaulHigin/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,TravisEz13/PowerShell,TravisEz13/PowerShell,TravisEz13/PowerShell,JamesWTruher/PowerShell-1,JamesWTruher/PowerShell-1,daxian-dbw/PowerShell