This commit changes `getTemplateAtTarget` to be able to identify when a
cursor position is specifically within the argument span of a `MethodCall`
or `SafeMethodCall` with no arguments. If the call had arguments, one of the
argument expressions would be returned instead, but in a call with no
arguments the tightest node _is_ the `MethodCall`. Adding the additional
argument context will allow for functionality that relies on tracking
argument positions, like `getSignatureHelpItems`.
PR Close#41581
d85e74e05c