Match keyword when it's at the start of the line

[dakennguyen]

Previously on my PR #79, these 3 scenarios are working:

# "if" is not at the start of a line -> end is added
class SomeClass
  if flag
  end 
...

# "if" is right after an equal sign -> end is added
tmp = if flag
      end

# "if" is not after an equal sign -> end is not ended
return "ok" if flag

However, I couldn't handle the case when some of the keywords are at the beginning of a line. Now this PR should do the trick:

# "if" is at the start of a line -> end is added
if flag
end

[windwp]

thank