lang/crystal: Update to 1.5.1

ChangeLog: https://github.com/crystal-lang/crystal/releases/tag/1.5.1

• Fix Class#nilable? for recursive unions and root types
• Fix Float#abs and Number#format for -0.0
• Fix null dereference when passing empty slice to Base64.encode
• Do not check abstract def parameter names on abstract types and modules
• Compiler/codegen: reset @needs_value
• Fix homogeneous_aggregate? check for aarch64 types
• Compiler: don't eagerly check cast type
• Fix type restriction augmenter for Union(*T) and similar
• Formatter: Fix assign followed by comment
• Handle formatting annotated method parameters
• Update distribution-scripts
• Update distribution-scripts
• [CI] Bumping xcode to 13.4.1

PR: 266519
Reported by: gspurki@gmail.com
Approved by: greg@unrelenting.technology (maintainer, timeout > 2 weeks)