[PATCH v3 2/3] emacs: create patch filename from subject for inline patch fake parts

Use the mail subject line for creating a descriptive filename for the wash generated inline patch fake parts. The names are similar to the ones created by 'git format-patch'. If the user has notmuch-wash-convert-inline-patch-to-part hook enabled in notmuch-show-insert-text/plain-hook, this will ch

[PATCH v3 2/3] emacs: create patch filename from subject for inline patch fake parts

Use the mail subject line for creating a descriptive filename for the wash generated inline patch fake parts. The names are similar to the ones created by 'git format-patch'. If the user has notmuch-wash-convert-inline-patch-to-part hook enabled in notmuch-show-insert-text/plain-hook, this will ch