Fix syntax highlighting with "~S" sigil (elixir-editors#457)

Fixes elixir-editors#438

Author: feliperenan

spec/syntax/doc_spec.rb

@@ -35,6 +35,17 @@
  expect(ex).to include_elixir_syntax('elixirDocString', 'foo')
  end
 
+ it 'doc with sigil_S triple double-quoted multiline content with parentheses' do
+ ex = <<~'EOF'
+ @doc(~S"""
+ foo
+ """)
+ EOF
+ expect(ex).to include_elixir_syntax('elixirVariable', 'doc')
+ expect(ex).to include_elixir_syntax('elixirSigilDelimiter', 'S"""')
+ expect(ex).to include_elixir_syntax('elixirSigil', 'foo')
+ end
+
  it 'doc with sigil_S triple single-quoted multiline content' do
  ex = <<~'EOF'
  @doc ~S'''
@@ -46,6 +57,17 @@
  expect(ex).to include_elixir_syntax('elixirDocString', 'foo')
  end
 
+ it 'doc with sigil_S triple single-quoted multiline content with parentheses' do
+ ex = <<~'EOF'
+ @doc(~S'''
+ foo
+ ''')
+ EOF
+ expect(ex).to include_elixir_syntax('elixirVariable', 'doc')
+ expect(ex).to include_elixir_syntax('elixirSigilDelimiter', "S'''")
+ expect(ex).to include_elixir_syntax('elixirSigil', 'foo')
+ end
+
  it 'doc with triple single-quoted multiline content is not a doc string' do
  ex = <<~'EOF'
  @doc '''

spec/syntax/sigil_spec.rb

@@ -10,6 +10,20 @@
  expect('def f(~s(")), do: true').not_to include_elixir_syntax('elixirSigilDelimiter', '"')
  end
 
+ it 'as function argument multiline content' do
+ ex = <<~'EOF'
+ f(
+ ~S"""
+ foo
+ """,
+ bar
+ )
+ EOF
+
+ expect(ex).to include_elixir_syntax('elixirSigilDelimiter', 'S"""')
+ expect(ex).to include_elixir_syntax('elixirSigil', 'foo')
+ end
+
  describe 'upper case' do
  it 'string' do
  expect('~S(string)').to include_elixir_syntax('elixirSigilDelimiter', 'S')

syntax/elixir.vim

@@ -103,8 +103,8 @@ syn region elixirSigil matchgroup=elixirSigilDelimiter start="\~\l("
 syn region elixirSigil matchgroup=elixirSigilDelimiter start="\~\l\/" end="\/" skip="\\\\\|\\\/" contains=@elixirStringContained,elixirRegexEscapePunctuation fold
 
 " Sigils surrounded with heredoc
-syn region elixirSigil matchgroup=elixirSigilDelimiter start=+\~\a\z("""\)+ end=+^\s*\zs\z1\s*$+ skip=+\\"+ fold
-syn region elixirSigil matchgroup=elixirSigilDelimiter start=+\~\a\z('''\)+ end=+^\s*\zs\z1\s*$+ skip=+\\'+ fold
+syn region elixirSigil matchgroup=elixirSigilDelimiter start=+\~\a\z("""\)+ end=+^\s*\z1+ skip=+\\"+ fold
+syn region elixirSigil matchgroup=elixirSigilDelimiter start=+\~\a\z('''\)+ end=+^\s*\z1+ skip=+\\'+ fold
 
 " Documentation
 if exists('g:elixir_use_markdown_for_docs') && g:elixir_use_markdown_for_docs