This is just some minor whitelisting/additions to dictionaries to catch
up between when the spell checker PR was written and when it was finally
merged.
This is basically taking the spelling output from
499f24a29e and putting it into files.
The choice of files is arbitrary. I'm adding a `math.txt` dictionary
because it's a reasonable example.
The goal here is to get master to a green check mark
## Validation
When I pushed this commit to my fork, the spell check action ran and
gave me a check mark: https://github.com/jsoref/terminal/runs/534783276
This commit introduces a github action to check our spelling and fixes
the following misspelled words so that we come up green.
It also renames TfEditSes to TfEditSession, because Ses is not a word.
currently, excerpt, fallthrough, identified, occurred, propagate,
provided, rendered, resetting, separate, succeeded, successfully,
terminal, transferred, adheres, breaks, combining, preceded,
architecture, populated, previous, setter, visible, window, within,
appxmanifest, hyphen, control, offset, powerpoint, suppress, parsing,
prioritized, aforementioned, check in, build, filling, indices, layout,
mapping, trying, scroll, terabyte, vetoes, viewport, whose
