fix(style): use double quotes in tool_name_validation.py per ruff config

Replace single-quoted string literals with double quotes in
BIDIRECTIONAL_FORMATTING_CHARS set and unicodedata.normalize call.

Author: manjunathbhaskar

src/mcp/shared/tool_name_validation.py

@@ -26,18 +26,18 @@
 
 # Bidirectional formatting characters that can be used to obfuscate tool names
 BIDIRECTIONAL_FORMATTING_CHARS = {
-    '‎',  # LEFT-TO-RIGHT MARK
-    '‏',  # RIGHT-TO-LEFT MARK
-    '‪',  # LEFT-TO-RIGHT EMBEDDING
-    '‫',  # RIGHT-TO-LEFT EMBEDDING
-    '‬',  # POP DIRECTIONAL FORMATTING
-    '‭',  # LEFT-TO-RIGHT OVERRIDE
-    '‮',  # RIGHT-TO-LEFT OVERRIDE
-    '⁦',  # LEFT-TO-RIGHT ISOLATE
-    '⁧',  # RIGHT-TO-LEFT ISOLATE
-    '⁨',  # FIRST STRONG ISOLATE
-    '⁩',  # POP DIRECTIONAL ISOLATE
-    '؜',  # ARABIC LETTER MARK
+    "‎",  # LEFT-TO-RIGHT MARK
+    "‏",  # RIGHT-TO-LEFT MARK
+    "‪",  # LEFT-TO-RIGHT EMBEDDING
+    "‫",  # RIGHT-TO-LEFT EMBEDDING
+    "‬",  # POP DIRECTIONAL FORMATTING
+    "‭",  # LEFT-TO-RIGHT OVERRIDE
+    "‮",  # RIGHT-TO-LEFT OVERRIDE
+    "⁦",  # LEFT-TO-RIGHT ISOLATE
+    "⁧",  # RIGHT-TO-LEFT ISOLATE
+    "⁨",  # FIRST STRONG ISOLATE
+    "⁩",  # POP DIRECTIONAL ISOLATE
+    "؜",  # ARABIC LETTER MARK
 }
 
 
@@ -92,7 +92,7 @@ def validate_tool_name(name: str) -> ToolNameValidationResult:
     # NFKC is the compatibility normalization form that converts:
     # - Fullwidth characters to ASCII (ａ → a)
     # - Composed characters to canonical form
-    normalized = unicodedata.normalize('NFKC', name)
+    normalized = unicodedata.normalize("NFKC", name)
     if normalized != name:
         warnings.append(
             f"Tool name contains Unicode characters that normalize to a different form. "