fix main return bug

[wu452148993]

fix two problem.
1.

result:

'jump 7 always's goal is empty.
2.

result:

'set @counter @funcTramp_main' funcTramp_main is empty
Solution:
I translate all 'return' in the main function into 'end', and add 'end' at the end of main function by default.
Problem:
Then we need to add end at the 'end' of all test cases,I think it's a bit strange. lol

[codecov]

Codecov Report

Merging #6 (5c6f3cc) into master (465fc39) will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master       #6      +/-   ##
==========================================
+ Coverage   89.72%   89.81%   +0.08%     
==========================================
  Files          29       29              
  Lines        2181     2189       +8     
==========================================
+ Hits         1957     1966       +9     
+ Misses        160      158       -2     
- Partials       64       65       +1     

Impacted Files	Coverage Δ
transpiler/main.go	91.51% <100.00%> (+0.15%)	⬆️
transpiler/type_native.go	100.00% <100.00%> (ø)
transpiler/type_mlog.go	67.85% <0.00%> (+1.78%)	⬆️

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