Update examples to bold terms consistently

[sirosen]

The following terms are identified here and bolded:

• flow
• flow definition
• flow run
• run
• state (in a flow)
• collection (GCS/Transfer)

Notable variations on this:

• In some contexts, we write "Guest Collection" -- these are left
  as-is for now, with no boldfacing.
  (Should it be **guest collection**?)

• Globus-provided Flow has converted to
  Globus-provided **flow**

• We write **run** ID, rather than **run ID** or similar.

[kurtmckee]

I'm not yet convinced that bolding terms throughout is helpful, but if this is the direction we're going then I've left feedback about some instances that caught my eye. 👍

[sirosen]

I'm not yet convinced that bolding terms throughout is helpful, but if this is the direction we're going

I want to make sure we're in sync that this isn't a new initiative -- it's the style guidance we already established for the docs site itself when we were struggling with how to present flows and runs.
We haven't done an enforcement pass, but for new content I'm trying to keep us in line with our prior decision. (And documenting said style guidance would help too, which I don't think we ever did.)

I'm not without any hesitancy around how we implement this guidance -- when we mesh these docs with other entities like collections we may end up making the docs in aggregate less coherent in style -- but we've had enough confusion around Flows¹ vs Flows² that I'm onboard with the idea that Title Case is not a good/sufficient way to present these things.

We can change our desired styling, but I want to make sure we're clear that this PR isn't introducing said styling.

Footnotes

1. short for "Globus Flows", duh! ↩

2. the Flows which belong to a user, also duh! ↩