refactor(ftplugin/man.vim): rearrange setlocal commands

Problem:
1. multiple `setlocal` commands are spread across the script.
2. several options, apparently, serve the same purpose (hide UI columns) which may not be immediately clear. more options may be required to fullfill the same purpose or they could be removed all together as a group if better solution is found later
3. `setlocal nofoldenable` may be overriden by conditional block later in the script.

Solution:
1. move 'colorcolumn' and 'nolist' to the group of other options at the beginning
2. add an explanatory comment about options that disable UI columns
3. move 'nofoldenable' to the if-else block to keep relevant commands coupled

runtime/ftplugin/man.vim

@@ -8,14 +8,16 @@ let b:did_ftplugin = 1
 
 setlocal noexpandtab tabstop=8 softtabstop=8 shiftwidth=8
 setlocal wrap breakindent linebreak
+setlocal colorcolumn=0 nolist
 
 " Parentheses and '-' for references like `git-ls-files(1)`; '@' for systemd
 " pages; ':' for Perl and C++ pages.  Here, I intentionally omit the locale
 " specific characters matched by `@`.
 setlocal iskeyword=@-@,:,a-z,A-Z,48-57,_,.,-,(,)
 
-setlocal nonumber norelativenumber
-setlocal foldcolumn=0 colorcolumn=0 nolist nofoldenable
+" man page content is likely preformatted for the terminal width, so
+" narrowing display by any additional columns leads to Embarrassing Line Wrap
+setlocal nonumber norelativenumber foldcolumn=0
 
 setlocal tagfunc=v:lua.require'man'.goto_tag
 
@@ -35,6 +37,8 @@ if get(g:, 'ft_man_folding_enable', 0)
   setlocal foldenable
   setlocal foldmethod=indent
   setlocal foldnestmax=1
+else
+  setlocal nofoldenable
 endif
 
 let b:undo_ftplugin = ''