Fix remote viewing setup doc
SSH command should specific localport:remotehost:remoteport rather than localport:localhost:remoteport in -L switch. Changed description for clarity.
* Add the following fixes to documentation:
* Fix trailing backslash in “Use docker image” section
* Replace escaped backslash with double-escaped backslash (see Sphinx issue: https://github.com/sphinx-doc/sphinx/issues/6730)
* Close backtick in `contributing.md`
* Add “run” to instructions for “Render Video”
* Remove unnecessary “,” in “Render Video”
* Correct “before preceding” to “before proceeding”
* Correct “viewpoinrts” to “viewpoints”
* Add missing “.” in “Process data”
* Specify “bash” for code blocks (for consistency with other blocks in the page)
* Fix code block in `viewer_quickstart.rst` (”Copy to clipboard” widget now works)
* Fix some code formatting issues in `export_geometry.md`
* Correct "harmoincs" to "harmonics" in docs.
