341: Add counts for replacement arguments

Ported: tpope#341

doc/surround.txt

@@ -96,7 +96,7 @@ All targets are currently just one character.
 
 Eight punctuation marks, (, ), {, }, [, ], <, and >, represent themselves
 and their counterparts.  If the opening mark is used, contained whitespace is
-also trimmed.  The targets b, B, r, and a are aliases for ), }, ], and > 
+also trimmed.  The targets b, B, r, and a are aliases for ), }, ], and >
 (the first two mirror Vim; the second two are completely arbitrary and
 subject to change).
 
@@ -129,6 +129,12 @@ b, B, r, and a are aliases for ), }, ], and >.  To fulfill the common need for
 code blocks in C-style languages, <C-}> (which is really <C-]>) adds braces on
 lines separate from the content.
 
+If a single digit number is used, the remaining replacement argument is
+repeated by that count.
+
+  Old text                  Command           New text ~
+  hello                     ysW2*             **hello**
+
 If t or < is used, Vim prompts for an HTML/XML tag to insert.  You may specify
 attributes here and they will be stripped from the closing tag. If replacing a
 tag, its attributes are kept in the new tag. End your input with > to discard

import/surround.vim

@@ -18,7 +18,7 @@ enddef
 def InputReplacement(): string
   var c = getcharstr()
 
-  if c == " "
+  if c =~ '[ 0-9]'
     c ..= getcharstr()
   endif
 
@@ -135,8 +135,14 @@ def Wrap(str: string, char: string, wrapType: string, removed: string, linebreak
   var before = ""
   var after = ""
   var initSpaces = linemode ? matchstr(keeper, '\%^\s*') : matchstr(getline('.'), '\%^\s*')
+  var scount = 1
   var extraspace = ""
 
+  if newchar =~ '^[0-9]'
+    scount = newchar->strpart(0, 1)->str2nr()
+    newchar = newchar->strpart(1)
+  endif
+
   if newchar =~ '^ '
     newchar = newchar->strpart(1)
     extraspace = ' '
@@ -258,6 +264,18 @@ def Wrap(str: string, char: string, wrapType: string, removed: string, linebreak
     after  = ''
   endif
 
+  if before =~ '.*\n\t$'
+    before = repeat(before->substitute('\n\t', '', ''), scount) .. '\n\t'
+  else
+    before = repeat(before, scount)
+  endif
+
+  if after =~ '.*\n\t$'
+    after = repeat(after->substitute('\n\t', '', ''), scount) .. '\n\t'
+  else
+    after = repeat(after, scount)
+  endif
+
   after = after->substitute('\n', '\n' .. initSpaces, 'g')
 
   if wrapType ==# 'V' || (linebreak && wrapType ==# "v")