Fix doc sigil with paren

Fixes #477

Author: jbodah

syntax/elixir.vim

@@ -125,15 +125,15 @@ else
   syn region elixirDocTest start="^\s*\%(iex\|\.\.\.\)\%((\d*)\)\?>\s" end="^\s*$" contained
 endif
 
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\s\+\)\@<=\~[Ss]\z(/\|\"\|'\||\)" end="\z1" skip="\\\\\|\\\z1" contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\s\+\)\@<=\~[Ss]{"                end="}"   skip="\\\\\|\\}"   contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\s\+\)\@<=\~[Ss]<"                end=">"   skip="\\\\\|\\>"   contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\s\+\)\@<=\~[Ss]\["               end="\]"  skip="\\\\\|\\\]"  contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\s\+\)\@<=\~[Ss]("                end=")"   skip="\\\\\|\\)"   contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocStringDelimiter start=+\%(@\w*doc\s\+\)\@<=\z("\)+                 end=+\z1+ skip=+\\\\\|\\\z1+ contains=@elixirDocStringContained      keepend
-syn region elixirDocString matchgroup=elixirDocStringDelimiter start=+\%(@\w*doc\s\+\)\@<=\z("""\)+               end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start=+\%(@\w*doc\s\+\)\@<=\~[Ss]\z('''\)+         end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
-syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start=+\%(@\w*doc\s\+\)\@<=\~[Ss]\z("""\)+         end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]\z(/\|\"\|'\||\)" end="\z1" skip="\\\\\|\\\z1" contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]{"                end="}"   skip="\\\\\|\\}"   contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]<"                end=">"   skip="\\\\\|\\>"   contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]\["               end="\]"  skip="\\\\\|\\\]"  contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start="\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]("                end=")"   skip="\\\\\|\\)"   contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocStringDelimiter start=+\%(@\w*doc\(\s\|(\)\+\)\@<=\z("\)+                 end=+\z1+ skip=+\\\\\|\\\z1+ contains=@elixirDocStringContained      keepend
+syn region elixirDocString matchgroup=elixirDocStringDelimiter start=+\%(@\w*doc\(\s\|(\)\+\)\@<=\z("""\)+               end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start=+\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]\z('''\)+         end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
+syn region elixirDocString matchgroup=elixirDocSigilDelimiter  start=+\%(@\w*doc\(\s\|(\)\+\)\@<=\~[Ss]\z("""\)+         end=+^\s*\z1+                contains=@elixirDocStringContained fold keepend
 
 " Defines
 syn match elixirDefine              '\<def\>\(:\)\@!'             nextgroup=elixirFunctionDeclaration        skipwhite skipnl