Proposing a PR to fix a few small typos

[timgates42]

Issue Type

[x] Bug (Typo)

Steps to Replicate and Expected Behaviour

• Examine docs/developer_guide.rst, docs/user_guide.rst and observe optionnal, however expect to see optional.
• Examine bakthat/init.py, docs/user_guide.rst and observe exlude, however expect to see exclude.
• Examine bakthat/init.py and observe paramter, however expect to see parameter.
• Examine bakthat/plugin.py and observe optionnaly, however expect to see optionally.
• Examine docs/user_guide.rst and observe mannualy, however expect to see manually.
• Examine test_bakthat.py and observe inital, however expect to see initial.
• Examine docs/user_guide.rst and observe extention, however expect to see extension.
• Examine docs/_themes/README.rst and observe drivative, however expect to see derivative.
• Examine bakthat/sync.py and observe concatened, however expect to see concatenated.
• Examine bakthat/backends.py and observe callbak, however expect to see callback.

Notes

Semi-automated issue generated by
https://github.com/timgates42/meticulous/blob/master/docs/NOTE.md

To avoid wasting CI processing resources a branch with the fix has been
prepared but a pull request has not yet been created. A pull request fixing
the issue can be prepared from the link below, feel free to create it or
request @timgates42 create the PR. Alternatively if the fix is undesired please
close the issue with a small comment about the reasoning.

https://github.com/timgates42/bakthat/pull/new/bugfix_typos

Thanks.