Having collection caching that wraps templates and automatically tries
to infer if they are cachable proved to be too much of a hassle.
We'd rather have it be something you explicitly turn on.
This removes much of the code and docs to explain the previous automatic
behavior.
This change also removes scoped cache keys and passing cache_options.
If a template includes `# Template Collection: ...` anywhere in its
source, that name will be used as the cache name for the partial that is
rendered for the collection.
This allows users to enable collection caching even if the template
doesn't start with `<% cache ... do %>`.
Moreover, the `# Template Collection: ...` notation is recognized in all
template types (and template types other than ERB can define a
resource_cache_call_pattern method to allow the `cache ... do` pattern
to be recognized too).
The regular expression which was used to detect partial templates that
begin with a `<% cache ... do %>` call missed some cases. This commits
attempts to improve the detection for some cases such as multi-line
comments at the beginning of the template. The different templates are
listed in two new unit test methods.
Note that specially crafted Ruby code can still evade such `cache`-call
detection: for example, a user might have its own method which itself
calls the Rails `cache` helper. In such a case, the template's code
doesn't start with a literal `cache` string and therefore will not be
eligible for collection caching.
The testing of error messages have been implemented wrongly a few times.
This is an attempt to fix it.
For example, some of these test should have failed with the new code.
The reason they are not failling with the new string is the fact they
were not being tested beforehand.
