Introduced "multipart/mixed" and "multipart/related" content types in encoding.go and updated msgwriter.go to accommodate these. Adjustments made in related tests for these new types. Additionally, removed unnecessary print statements and improved multipart alternative parsing in eml.go.
Added "References" header field to cover more potential use cases and enhance versatility. This field will allow applications to track series of related messages.
Test for "References" field has also been added for validation.
Also included are string methods for Content-type objects with relevant tests, ensuring accurate string conversion. Unnecessary duplicate method of string conversion for Charset has been removed to streamline the code and improve readability.
# SUMMARY
* Bad licenses:
* Deprecated licenses:
* Licenses without file extension:
* Missing licenses:
* Unused licenses:
* Used licenses: CC0-1.0, MIT
* Read errors: 0
* Files with copyright information: 45 / 45
* Files with license information: 45 / 45
Congratulations! Your project is compliant with version 3.0 of the REUSE Specification :-)