- Prevent generation_date tag format from being modified when SAVE_DATE_FORMAT is
specified
- Prevent NoneType from ending up in the tags (previous fix did not work)
- Update DATE_FORMAT to be configurable using the SAVE_DATE_FORMAT environment variable
- Modify target filename generation to handle cases where SAVE_DATE_FORMAT is left blank
- Default to date format "%Y-%m-%d" if SAVE_DATE_FORMAT is not set
'save' can be used to save a Markdown file, with optional frontmatter
and additional tags. By default, if set, `FABRIC_FRONTMATTER_TAGS` will
be placed into the file as it is written. These tags and front matter
are suppressed from STDOUT, which can be piped into other patterns or
programs with no ill effects. This strives to be a version of `tee` that
is enhanced for personal knowledge systems that use frontmatter.