Add -render-type-content option to render full type content instead of an ellipsis (`{ ... }`)

[alexandregv]

Adds a -render-type-content bool flag which allows to control wether you want to replace types content with an ellipsis or not.
It defaults to false, to keep the current behavior.

Example with -render-type-content=true:

type Config struct { ... }

becomes

type Config struct {
    Username      string `json:"username"`
    Password      string `json:"password"`
}

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 69.87%. Comparing base (8283e66) to head (1ef7e79). Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #129 +/- ## ======================================= Coverage 69.87% 69.87% ======================================= Files 3 3 Lines 83 83 ======================================= Hits 58 58 Misses 15 15 Partials 10 10 ```

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[posener]

Maybe add a test? Also update pr text? Thanks!

[alexandregv]

Just added a test, and changed PR text.