treesitter: implement strings completely (#3007)

follow up to #2902

utils/treesitter/testdata/string/block_inside_quotes.carbon

@@ -0,0 +1,8 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = '''
+  '' ''
+  ' ' '
+''';

utils/treesitter/testdata/string/fail_block_not_enough_quotes.carbon

@@ -0,0 +1,7 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = ''
+  hello
+  '';

utils/treesitter/testdata/string/fail_block_single_quote.carbon

@@ -0,0 +1,7 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = '
+  single quote
+';

utils/treesitter/testdata/string/fail_block_unclosed_string.carbon

@@ -0,0 +1,6 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var x: String = '''
+unclosed string

utils/treesitter/testdata/string/fail_newline.carbon

@@ -0,0 +1,6 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var x: String = "new
+line";

utils/treesitter/testdata/string/fail_raw_block_more_hash_tags_on_left.carbon

@@ -0,0 +1,7 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = ##'''
+  error: there are more #s on the left than the right.
+'''#;

utils/treesitter/testdata/string/fail_raw_block_more_hash_tags_on_right.carbon

@@ -0,0 +1,7 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = #'''
+  error: there are more #s on the right than the left.
+'''##;

utils/treesitter/testdata/string/fail_raw_block_quotes_not_on_own_line.carbon

@@ -0,0 +1,6 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = #'''
+  error: closing not on own line '''#;

utils/treesitter/testdata/string/fail_raw_more_hash_tags_on_left.carbon

@@ -0,0 +1,5 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = ##"str"#;

utils/treesitter/testdata/string/fail_raw_more_hash_tags_on_right.carbon

@@ -0,0 +1,5 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = "str"#;

utils/treesitter/testdata/string/fail_simple_escaped_newline.carbon

@@ -0,0 +1,6 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: String = "hello\
+world";

utils/treesitter/testdata/string/fail_unclosed_string.carbon

@@ -0,0 +1,5 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+var s: "