Minor grammar fix in manpages
Fix documentation url
Allow hacking/env-setup module path to use config file library path

hacking/env-setup now adds the configured library path in ANSIBLE_CONFIG
to the ANSIBLE_LIBRARY environment variable in addition to the previous
default of ANSIBLE_HOME/library.

This replaces #5950.
Merge pull request #5967 from willthames/env_setup_library

Allow hacking/env-setup module path to use config file library path
mention that include works with addtional task files

Mention we can include roles/x/tasks/anothertasks.yml with `include anothertasks.yml` within the role's `main.yml` as this is not obvious from the documentation
Merge pull request #5972 from mmoya/docfix

Minor grammar fix in manpages and update docs url.
Merge pull request #5974 from jakubholynet/patch-1

mention that include works with addtional task files