Move docxcompose to optional dependency

[waketzheng]

Description

Move docxcompose to optional group 'subdoc', which can be installed by: pip install "docxtpl[subdoc]"

Related issue: #605 #602

[svleeuwen]

Hi @waketzheng, thanks for this.

I'm just testing and getting an error because of the return type here:

    def new_subdoc(self, docpath=None) -> Subdoc:
        from .subdoc import Subdoc

        self.init_docx()
        return Subdoc(self, docpath)

This should use a string instead -> "Subdoc"

[waketzheng]

OK, I will fix it soon.

[waketzheng]

I'm just testing and getting an error because of the return type here:

    def new_subdoc(self, docpath=None) -> Subdoc:
        from .subdoc import Subdoc

        self.init_docx()
        return Subdoc(self, docpath)

This should use a string instead -> "Subdoc"

@svleeuwen Fixed by #619 in favor of the from __future__ import annotations import