* lisp/progmodes/ruby-mode.el (ruby-smie--args-separator-p): Allow the
first arg to be a string (fixed dead code), or an operator symbol.
(ruby-smie--forward-token): Tokenize ` @ ' before strings and
operator symbols.
(ruby-smie-rules): Remove parent token check in the `.' clause, it
did nothing. Don't respond to `(:after ".")', it will be called
with :before anyway. Remove the ` @ ' rule, it didn't seem to
change anything. Only return indentation for binary operators
when they are hanging. De-dent opening paren when its parent is
`.', otherwise it looks bad when the dot is not at bol or eol.