Support Korean Fonts in textproc/docproj

[wblock]

Summary

Add korean/nanum-fonts-ttf as a dependency to the textproc/docproj port when CJK is enabled.

From suggestion by Hoyoung Kim in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=202699.

Test Plan

Check that dependency on korean/nanum-fonts-ttf is added to textproc/docproj. (It does.)
Check that PDF of article translated to Korean shows the fonts instead of "#" for missing font characters. (It does.)
Check that PDF of article translated to Korean builds the fonts into the PDF. (It does.)