v1.21.0 - Even more examples of categories with interesting property combinations

Just like the previous release, this release mainly adds several categories that satisfy interesting property combinations that had not been witnessed before, cf. this milestone.

Database 🔋

• Consistent usage of essentially small collections by @ScriptRaccoon in #367
• Add the category of large families of vector spaces with ess. small support by @ScriptRaccoon in #365
• Pullbacks imply coreflexive equalizers by @ScriptRaccoon in #368
• Add three categories of large families of sets by @ScriptRaccoon in #369
• The category of directed graphs and the category of sets with a binary relation by @ScriptRaccoon in #372
• The category of metric spaces has no regular subobject classifier by @ScriptRaccoon in #378
• Add a large indiscrete category by @ScriptRaccoon in #384
• Add various categories with subobject classifiers by @ScriptRaccoon in #371

Features 🧪

• Keep order of related structures by @ScriptRaccoon in #377
• Add link to dual implication on implication page by @ScriptRaccoon in #379
• Text update script by @ScriptRaccoon in #385

Infrastructure 💻

• Add cspell as dev dependency by @ScriptRaccoon in #376

Refactor 🧹

• Minor database improvements by @ScriptRaccoon in #380
• Validate seed files by @ScriptRaccoon in #381

Full Changelog ⚙️

v1.20.0...v1.21.0