fix(src): fix URL

[kariya-mitsuru]

Types of changes

• Enhancement (project structure, spelling, grammar, formatting)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

A description of the changes proposed in the Pull Request

Following the change in documentation URL.

[narekhovhannisyan]

@kariya-mitsuru Thanks for contributing! I think it will be better to update the reference of documentation to use term manifest instead of imp.

cc: @jmcook1186

[jmcook1186]

Hi @narekhovhannisyan actually I deliberately changed the docs to use the IMP terminolgoy, so the proposed change is appropriate.