Add leading space replacement

doc/surround.txt

@@ -133,6 +133,9 @@ attributes here and they will be stripped from the closing tag.  End your
 input by pressing <CR> or >.  If <C-T> is used, the tags will appear on lines
 by themselves.
 
+If s is used, a leading but not trailing space is added.  This is useful for
+removing parentheses from a function call with csbs.
+
 CUSTOMIZING                                     *surround-customizing*
 
 The following adds a potential replacement on "-" (ASCII 45) in PHP files.

plugin/surround.vim

@@ -159,6 +159,9 @@ function! s:wrap(string,char,type,...)
   elseif newchar ==# "p"
     let before = "\n"
     let after  = "\n\n"
+  elseif newchar ==# 's'
+    let before = ' '
+    let after  = ''
   elseif newchar =~# "[tT\<C-T><,]"
     let dounmapp = 0
     let dounmapb = 0