multiple changes for nvim

- tex snippets were changed for listed and unlisted sections
- nvim autocompletion engine was swapped to nvim-cmp
- nvim clears more files when exiting tex files
- the compiler uses biber when compiling tex files
- sc-im is used for .sc filetypes when using vifm

.config/vifm/vifmrc

@@ -177,7 +177,7 @@ fileviewer *.pdf
 		"\ pdftotext -nopgbrk %c -
 
 " CSV
-filetype *.csv,*.xlsx sc-im %f
+filetype *.csv,*.xlsx,*.sc sc-im %f
 
 " PostScript
 filextype *.ps,*.eps,*.ps.gz