Build metadata does not affect precedence (SemVer 2.0.0 §10), so
the Eq and Neq constraints now use SemanticVersionComparer.Priority
instead of the structural == operator. This makes [1.2.3] match
1.2.3+build, consistent with precedence semantics.
Add a failing-then-passing test.
Per SemVer 2.0.0 the core version numbers and numeric prerelease
identifiers must not include leading zeroes, and prerelease/build-metadata
identifiers must be composed only of ASCII alphanumerics and hyphens.
Add IsValidIdentifiers using a vectorized SearchValues lookup for the
allowed character set and ulong.TryParse to detect numeric identifiers
for the leading-zero check. Add failing-then-passing tests for both
invalid and still-valid inputs.
This removes the description from the package readme. The desciption of the package is
shown on nuget.org in the list view and if no package readme is defined on the detail view of
a package version. Since we provide a package readme we do not need the description shown
twice.
