* lisp/progmodes/ruby-mode.el (ruby-syntax-propertize-function):

* lisp/progmodes/ruby-mode.el (ruby-syntax-propertize-function):
Extract `ruby-syntax-propertize-expansions'.
(ruby-syntax-propertize-expansions): Only change syntax on
certain string delimiters, to punctuation.  This way the common
functions like forward-word and thing-at-point still work.
(ruby-match-expression-expansion): Improve readability.
(ruby-block-contains-point): New function.
(ruby-add-log-current-method): Handle several edge cases.

* test/automated/ruby-mode-tests.el
Rename one interpolation test; add three more.
(ruby-with-temp-buffer): New macro, use it where appropriate.
(ruby-add-log-current-method-examples): Use "_" for target point.
Add four tests for ruby-add-log-current-method.