Fix use of trailing dots on metric names in telemetry.mdx
Fix use of trailing dots on metric names in telemetry.mdx

In the metric documentation, some metrics are written with an extra
trailing dot character. Often this is just spurious. In some cases, it
is an allusion to the metric name having various variable dot-separated
parts (which really ought to be labels, but that's another issue).

1) Trim all the dots which are without meaning.

2) Explicitly show with placeholders in angle brackets, where there are
   variable parts.

3) Remove a `json` type indicator from a code block which was not JSON
   (rather Prometheus metrics) format, since my IDE was reporting the
   non-JSON syntax as an error.

4) Reformat each Markdown table which I had touched with other changes
   to have consistent column spacing in the source representation. As
   a result, this PR has a lot of whitespace changes, so please make use
   of GitHub's "ignore whitespace" checkbox in the PR diff viewer.

Let me know if you would prefer:

- to not accept the table spacing reformat in the same PR as other
  changes

- to not accept the table spacing reformat ever

- to have all tables in the file reformatted, not just ones touched with
  other changes

hashicorp/consul,hashicorp/consul,hashicorp/consul,hashicorp/consul