Caused by langtool-langauge-tool-jar not being set (because defvar won't
change a defined variable), and app/write/doctor.el uses it in a
file-exists-p call, which throws the stringp error if given anything
other than a string.
This removes the various doom-line-number* variables and replaces it
with the Emacs 26 display-line-numbers API, which I've ported to Emacs
25.x (however, it uses nlinum under the hood, and not all of
display-line-numbers options are supported).
+ Make synosaurus unconditional
+ Move much of +write-mode into its hook
+ Conform README.org to template and expand it
+ Try to guess langtool-language-tool-jar
+ Update init.example.el entry
+ Remove redundant variables
+ Add +write-text-scale & +text-line-spacing variables
