chore: clean up proto Value code

[muktihari]

• Update (Value) SliceBool code documentation: []bool into []typedef.Bool
• Simplify string len counting in proto.Sizeof
• Update switch's cases ordering to match proto Type's constants order for consistency.

[codecov-commenter]

Codecov Report

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

Project coverage is 100.00%. Comparing base (72de0f3) to head (bdc9293). Report is 1 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #435 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 42 42 Lines 3669 3658 -11 ========================================= - Hits 3669 3658 -11 ```

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