typo
Update chapters/23.markdown

Changes from `:help call` to `:help :call`.
Update 43.markdown

Very minor change, but something that threw me when I was adding a doc to a Vim plugin. Had to double check elsewhere that it was supposed to be "doc" instead of "docs".
More proofreading.
Proof 01-08.
Proof 09-12.
Proof 13-18.
Proof 19-26.
Proof 27-31.
Proof 32-37.
Proof 38-41.
Proof 42-48.
Proof 49-51.
Proof 52-56.
ack
Merge.
Merge.
Merge.
ack
Merge.