feat(Topology/EMetricSpace/Defs): add theorems EMetric.continuous*_iff*

[gilesgshaw]

Add 8 theorems of the form EMetric.continuous*_iff*, which are exactly analogous to
existing theorems of the form Metric.continuous*_iff*

---

Thus the API between the following files (already pretty consistent) is now more consistent
Topology.MetricSpace.Pseudo.Defs for PseudoMetricSpace
Topology.EMetricSpace.Defs for PseudoEMetricSpace

I have copied the theorems exactly (that is, changing only [e]dist and Pseudo[E]MetricSpace),
however perhaps there will be suggestions to make other changes at this opportunity.
(E.g. is it worth making the use of strict implicit parameters more consistent - possibly not?)

[github-actions]

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[github-actions]

PR summary f1e760eded

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff

+ continuousAt_iff
+ continuousAt_iff'
+ continuousOn_iff
+ continuousOn_iff'
+ continuousWithinAt_iff
+ continuousWithinAt_iff'
+ continuous_iff
+ continuous_iff'

You can run this locally as follows

## summary with just the declaration names:
./scripts/pr_summary/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh contains some details about this script.

---

No changes to technical debt.

You can run this locally as

./scripts/reporting/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[github-actions]

✅ PR Title Formatted Correctly

The title of this PR has been updated to match our commit style conventions.
Thank you!