Fix infinity loop issue

[loga4]

Pay attention, the @notice parameter of the assignVested method in the TokenManagercontract breaks theradspec` parser: there is a infinity loop.
There are several options on how to fix this:

1. Correct the notice in the TokenManager contract;
2. Add simple protection from infinity loop;
3. Add a validation check for the AST tree.

Considering that the radspec and Token Manager contract has not been updated for a long time - there is a proposal to go on the first and second point.

[CLAassistant]

All committers have signed the CLA.

[Voronchuk]

I don't see any security issues with this change

[githubdoramon]

@loga4 can you pls fix the lint issue?

[loga4]

@loga4 can you pls fix the lint issue?

oh, my bad, sorry)
done

[codecov]

Codecov Report

Merging #127 (040177a) into master (8aef856) will increase coverage by 1.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #127      +/-   ##
==========================================
+ Coverage   92.19%   93.23%   +1.04%     
==========================================
  Files          37       37              
  Lines         756      769      +13     
==========================================
+ Hits          697      717      +20     
+ Misses         59       52       -7     

Impacted Files	Coverage Δ
src/parser/index.js	90.09% <100.00%> (+4.38%)	⬆️

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