Fix typos in comments and docstrings (#2101)

Found by codespell:
- curent -> current (classes.py)
- suppport -> support, propeties -> properties (inference/__init__.py)
- existance -> existence (inference/analysis.py)
- Propably -> Probably (inference/value/instance.py)

Co-authored-by: maxtaran2010 <ocotifuzo727@gmail.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

jedi/inference/analysis.py

@@ -110,7 +110,7 @@ def _check_for_setattr(instance):
 
 def add_attribute_error(name_context, lookup_value, name):
     message = ('AttributeError: %s has no attribute %s.' % (lookup_value, name))
-    # Check for __getattr__/__getattribute__ existance and issue a warning
+    # Check for __getattr__/__getattribute__ existence and issue a warning
     # instead of an error, if that happens.
     typ = Error
     if lookup_value.is_instance() and not lookup_value.is_compiled():