chore: import upstream snapshot with attribution

python/semantic_kernel/template_engine/blocks/symbols.py

@@ -0,0 +1,22 @@
+# Copyright (c) Microsoft. All rights reserved.
+from enum import Enum
+
+
+class Symbols(str, Enum):
+    """Symbols used in the template engine."""
+
+    BLOCK_STARTER = "{"
+    BLOCK_ENDER = "}"
+
+    VAR_PREFIX = "$"
+
+    DBL_QUOTE = '"'
+    SGL_QUOTE = "'"
+    ESCAPE_CHAR = "\\"
+
+    SPACE = " "
+    TAB = "\t"
+    NEW_LINE = "\n"
+    CARRIAGE_RETURN = "\r"
+
+    NAMED_ARG_BLOCK_SEPARATOR = "="