Revert "Merge pull request #481 from WalterBright/inout-tag"

This reverts commit 9eac384d4b6ca09751e591d67eb4bdd1857450aa, reversing
changes made to dac3d7aacd960896e7a7b00b574464556f2701db.
fix Issue 11979 - inout const is not documented
Merge pull request #482 from 9rnsr/fix11979

Issue 11979 - inout const is not documented
Add documentation about "Nested template" feature.
Merge pull request #479 from 9rnsr/nested_template

Add documentation about "Nested template" feature.