Minor corrections.

Fixed typo: transacftion, now: transaction

Add in help message about troubleshooting where you cannot login to buildkit build because rewrite mod isn't enabled

Adds documentation for https://github.com/civicrm/civicrm-core/pull/10984

Use more consistent capitalization and typography

This opening tag used to be required for syntax highlighting to work
properly in code blocks. Now we no longer need it.

Add `karma` and `upgrade`. Reorder alphabetically.

Find/replace `(?<=\w) {2,}` with ` `

Remove "editorial" TODO item from "If the PR contains database upgrades".

With only one example, a reader might misinterpret the example as saying
that `Search Preferences` has been renamed `domain`.  Including two examples
should more clearly indicate that *all* group-names are now flattened to
just `domain`.

This section documents two distinct changes, but they had different
formatting -- which made it seem that (perhaps) the one code-block was
describing both changes.

This change uses similar formatting for both examples and changes the
indentation/alignment to indicate that they're distinct.

Removed extraneous space in **Viewing errors in logfiles**

Reading for content; editing for consistency. 
Updated per seamuslee001's comment, and I found another missed edit in the automate testing paragraph.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency. 
Note:  Check for Drupal dependencies in the DB upgrade case.

Reading for content; editing for consistency.

Reading for content; editing for consistency.

Reading for content; editing for consistency.