vifm: Add pdf, docx viewer options

Added opening of docx files from vifm through either pandoc
interpretation as markdown if installed, or docx2txt invocation as a
fallback. (pandoc generally interprets the layout better than docx2txt,
especially contained tables).

Similarly, added option to open pdfs with pdftotext program in neovim,
to edit/grep/view only the text without pdf markup in neovim.

Changed key binding to open selected file in neovim from `o` to `e`,
mimicking the edit command found in some other file viewers.

vifm/.config/vifm/vifmrc

@@ -111,8 +111,10 @@ set timeoutlen=5000
 mark h ~/
 mark d ~/downloads/
 mark p ~/projects/
+mark s ~/projects/studentassistant/
 mark i ~/pictures/
 mark n ~/documents/notes/
+mark N ~/Nextcloud/
 mark l ~/documents/library/academia/pdf/
 mark t ~/.local/share/vifm/Trash/
 
@@ -172,7 +174,11 @@ command! reload :write | restart
 " program.
 
 " Pdf
-filextype *.pdf zathura %c %i &, apvlv %c, xpdf %c
+filextype *.pdf
+        \ { view as rich file }
+        \ zathura %c %i &, apvlv %c, xpdf %c,
+        \ { edit text content }
+        \ pdftotext -nopgbrk %c - | nvim
 fileviewer *.pdf pdftotext -nopgbrk %c -
 
 " PostScript
@@ -334,10 +340,14 @@ fileviewer *.7z 7z l %c
 
 " Office files
 filextype *.odt,*.doc,*.docx,*.xls,*.xlsx,*.odp,*.pptx libreoffice %f &
-fileviewer *.doc catdoc %c | nvim
+filetype *.doc catdoc %c | nvim
 fileviewer *.doc catdoc %c
-filextype *.docx docx2txt %f - | nvim
-fileviewer *.docx docx2txt %f -
+filetype *.docx
+            \ pandoc -s -t markdown %f | nvim,
+            \ docx2txt %f - | nvim
+fileviewer *.docx
+            \ pandoc -s -t markdown %f,
+            \ docx2txt %f -
 
 " TuDu files
 filetype *.tudu tudu -f %c
@@ -431,7 +441,7 @@ nnoremap w :view<cr>
 vnoremap w :view<cr>gv
 
 " Open file in existing instance of nvim
-nnoremap o :!nvim <cr>
+nnoremap e :!nvim %f<cr>
 
 " Open file in the background using its default program
 nnoremap gb :file &<cr>l