Reword documentation for IOS L2/L3 interface modules

[RyanBreaker]

SUMMARY

There was a slight discrepency between wording choices in the documentation for the ios_l2_interface and ios_l3_interface modules. This PR just makes their wording more cohesive and also fixes a typo.

ISSUE TYPE

• Docs Pull Request

COMPONENT NAME

ios_l2_interface
ios_l3_interface

ANSIBLE VERSION

ansible 2.6.2
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/home/breaker/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.15 (default, May 16 2018, 17:50:09) [GCC 8.1.1 20180502 (Red Hat 8.1.1-1)]

ADDITIONAL INFORMATION

N/A

[ansibot]

cc @ganeshrn @Qalthos @rcarrillocruz
click here for bot help

[ansibot]

Hi @RyanBreaker,

Thank you for the pullrequest, just so you are aware we have a dedicated Working Group for network.
You can find other people interested in this in #ansible-network on Freenode IRC
For more information about communities, meetings and agendas see https://github.com/ansible/community

click here for bot help

[acozine]

@RyanBreaker thanks for reviewing the docs so carefully and for adding consistency to these two pages!