Added option for folding of usepackage (#477)

autoload/vimtex/fold.vim

@@ -26,6 +26,7 @@ function! vimtex#fold#init_options() " {{{1
         \   'subsection',
         \   'subsubsection',
         \ ])
+  call vimtex#util#set_default('g:vimtex_fold_usepackage', 1)
 
   " Disable manual mode in vimdiff
   let g:vimtex_fold_manual = &diff ? 0 : g:vimtex_fold_manual
@@ -140,6 +141,7 @@ function! vimtex#fold#level(lnum) " {{{1
   endif
 
   " Fold usepackages
+  if g:vimtex_fold_usepackage
     if line =~# '^\s*\\usepackage\s*\[\s*\%($\|%\)'
       let s:usepackage = 1
       return 'a1'
@@ -147,6 +149,7 @@ function! vimtex#fold#level(lnum) " {{{1
       let s:usepackage = 0
       return 's1'
     endif
+  endif
 
   " Fold chapters and sections
   for [part, level] in b:vimtex_fold.parts

doc/vimtex.txt

@@ -467,6 +467,18 @@ Options~
         \ "subsubsection",
       \ ]
 <
+*g:vimtex_fold_usepackage*
+  Use this option to disable/enable folding of long `\usepackage` lines. The
+  lines must be formatted like this for folding to work properly: >
+
+    \usepackage[
+      option 1,
+      ...,
+      option n
+      ]{name}
+<
+  Default value: 1
+
 *g:vimtex_imaps_enabled*
   Use this option to disable/enable the insert mode mappings.
 
@@ -1584,6 +1596,7 @@ Associated settings:
   |g:vimtex_fold_parts|
   |g:vimtex_fold_sections|
   |g:vimtex_fold_envs|
+  |g:vimtex_fold_usepackage|
 
 ==============================================================================
 INDENTATION                                                     *vimtex-indent*