@astrojs/starlight 0.5.6

#383 0ebc47e Thanks @delucis! - Fix edge case where index files in an index directory would end up with the wrong slug
#373 308b3aa Thanks @lorenzolewis! - Fix visual overflow for wide logos
#385 fb35397 Thanks @lorenzolewis! - Fix nested elements in markdown content
#386 e6f6f30 Thanks @huijing! - Prevent search keyboard shortcuts from triggering when input elements are focused