Let the reader knows that it will be cover

[thiagola92]

Just let the reader knows that manual merge is something that will be cover in the future and that the writer didn't abruptly change the subject to automatically fetch and merge.

• [X] I provide my work under the project license.
• [X] I grant such license of my work as is required for the purposes of future print editions to Ben Straub and Scott Chacon.

Changes

• Add few words to let reader knows that manual merge will be cover

Context

The subject changed from git fetch and manual merge to automatically fetch and merge with git pull.