Doc: Improve folding documentation

Related with comment in vhda#146.
Should also fix vhda#214.

Author: vhda

README.md

@@ -74,9 +74,12 @@ __Note__: Proper SystemVerilog tag generation requires development version of
 To enable syntax folding set the following option:
 
 ```VimL
+let g:verilog_syntax_fold_lst = "all"
 set foldmethod=syntax
 ```
 
+For more information check the help page `:help veriog-fold`.
+
 ### Verilog Compilation and Error format
 
 This plugin includes the [errorformat][vim-errorformat] configurations for

doc/verilog_systemverilog.txt

@@ -151,6 +151,10 @@ To enable syntax folding set the following option:
 Take into account that all folding is disabled by default and the list of
 items to be folded must be configured using |g:verilog_syntax_fold_lst|.
 
+The commands |VerilogFoldingAdd| and |VerilogFoldingRemove|, which support
+command line completion, can also be used to dynamically enable or disable
+folding for certain types of code.
+
 ------------------------------------------------------------------------------
 VERILOG ERROR FORMATS                                            *verilog-efm*