Prevent the counter cache from being decremented twice

when destroying a record on a has_many :through association.
:destroy method has own counter_cache callbacks.
documentation updated for Hashes [ci skip]
Merge pull request #12748 from dm1try/fix_counter_cache_for_through_association

Fixes #11079, prevent the counter cache from being decremented twice when destroying a record on a has_many :through association
Merge pull request #12854 from kuldeepaggarwal/f-indentation

methods and outputs indented [ci skip]
updated documentation for Integer
Make static error pages responsive
Merge pull request #12555 from EtienneLem/responsive-static-pages

Make static error pages responsive
Merge pull request #12857 from kuldeepaggarwal/f-indentation

updated documentation for Integer [ci skip]
Include URL helpers in TestController in bug report templates
[ci skip]

Fixes #12848.
Merge pull request #12851 from RKushnir/master

Include URL helpers in TestController in bug report templates [ci skip]