fix(templates): blog_meta category & tag classname (A)

[wesleyboar]

Description

• Build classname with automated, required, recognizable "slug" instead of empty "count".
• Classname has blog-categories-__SLUG__.
• Classname still has blog-categories-.

References

• fixes Markup of Category and Tag Links Have Incomplete Class #710

Checklist

• I have read the contribution guide
• Code lint checked via inv lint
• changes file included (see docs)
• Usage documentation added in case of new features
• Tests added

[yakky]

@wesleyboar thanks for detecting this, I should we should keep the classes compatible by adding the correct classes to the markup without replacing the wrong ones for at least a release cycle, to avoid breaking people relying on the existing classes

[coveralls]

Coverage: 96.961%. Remained the same when pulling 2f5ff30 on wesleyboar:patch-1 into 33e455d on nephila:develop.

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (33e455d) 94.24% compared to head (c46ca34) 94.24%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #711   +/-   ##
========================================
  Coverage    94.24%   94.24%           
========================================
  Files           26       26           
  Lines         1823     1823           
  Branches       260      260           
========================================
  Hits          1718     1718           
  Misses          53       53           
  Partials        52       52           

Flag	Coverage Δ
unittests	94.24% <ø> (ø)

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[wesleyboar]

This PR was automatically closed when I renamed its branch to try to make a certain "check" pass.

I have opened #730 instead (it also has the change you requested).