v2: fix bug: enums of underscored number (#1581)

[Nerzal]

Describe the PR
Bring latest change from master to v2 branch

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (c7b796d) 79.38% compared to head (469a0c3) 79.38%.

❗ Current head 469a0c3 differs from pull request most recent head 5f54ddb. Consider uploading reports for the commit 5f54ddb to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##               v2    #1592   +/-   ##
=======================================
  Coverage   79.38%   79.38%           
=======================================
  Files          21       21           
  Lines        5568     5570    +2     
=======================================
+ Hits         4420     4422    +2     
  Misses        974      974           
  Partials      174      174           

Impacted Files	Coverage Δ
package.go	73.33% <100.00%> (+0.51%)	⬆️

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[ubogdan]

Would you mind adding some unit tests to cover this change ?

[sdghchj]

Would you mind adding some unit tests to cover this change ?

I think there is no much need to add a single unit test.

const underscored = 1_000_000

This line has covered this change. swag will try to parse all the consts at first. if failed, errors will be reported.

And I will add more accurate test after next fix #1584. Have a look at #1593, please.