✅ Small PSR fix

Merge pull request #40 from parsica-php/patch-make-many-5x-faster

⚡️ Make many 400% faster by using while instead of recurse

♻️ Move the code from `Verraes\Parsica` to `Parsica\Parsica` namespace

As part of moving the package to an organisation, we decided to move the
namespace to Parsica. Sorry if this would break your integration!

/cc @mathiasverraes

DOCS Expressions: additions

DOCS Expressions

DOCS: removed link to installation instructions.

Docusaurus doesn't do well with ../path

psalm type fix

FIX: phpunit max nesting level

perf docs

dropped .md from doc links