Rename module ls_tools -> symbol_tools

(They are no longer limited to LS-based tools, as the editing tools can use a different underlying CodeEditor)

src/serena/tools/__init__.py

@@ -1,7 +1,7 @@
 # ruff: noqa
 from .tools_base import *
 from .file_tools import *
-from .ls_tools import *
+from .symbol_tools import *
 from .memory_tools import *
 from .cmd_tools import *
 from .config_tools import *