Update error doc strings

Co-authored-by: Nate Prewitt <[email protected]>

Author: JordonPhillips

codegen/core/src/main/java/software/amazon/smithy/python/codegen/generators/ServiceErrorGenerator.java

@@ -58,7 +58,7 @@ def __post_init__(self) -> None:
 
                     @dataclass
                     class $3L($1L):
-                        ""\"Error representing any unknown api errors""\"
+                        ""\"Error representing any unknown api errors.""\"
                         code: ClassVar[str] = 'Unknown'
                         fault: ClassVar[Literal["client", "server"]] = "client"
                     """, apiError.getName(), serviceError, unknownApiError.getName());