Enable IDE0083: UseNotPattern

[xtqqczze]

https://learn.microsoft.com/dotnet/fundamentals/code-analysis/style-rules/ide0083

Fix #26230

[Copilot]

Pull Request Overview

This PR enables the IDE0083 code style analyzer rule by upgrading it from "silent" to "warning" severity and refactors existing code to use the modern "is not" pattern syntax instead of the older "!(x is Type)" negated type check pattern. This improves code readability and aligns with current C# best practices.

Key changes:

• Updated .globalconfig to enforce IDE0083 as a warning
• Replaced negated type checks !(x is Type) with the cleaner x is not Type pattern across multiple files

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.globalconfig	Changed IDE0083 severity from silent to warning to enforce the pattern
src/System.Management.Automation/help/ProviderContext.cs	Modernized type check pattern in provider help retrieval
src/System.Management.Automation/help/CommandHelpProvider.cs	Modernized type check pattern in help data processing
src/System.Management.Automation/engine/parser/ast.cs	Updated multiple type check patterns in AST-related methods including equality checks and value assignments
src/System.Management.Automation/engine/parser/TypeResolver.cs	Modernized type check pattern in equality comparison
src/System.Management.Automation/engine/parser/TypeInferenceVisitor.cs	Updated type check patterns in type inference logic
src/System.Management.Automation/engine/parser/SemanticChecks.cs	Modernized type check patterns in semantic validation
src/System.Management.Automation/engine/parser/Position.cs	Updated type check pattern in extent equality check
src/System.Management.Automation/engine/parser/Parser.cs	Modernized type check patterns in hashtable parsing
src/System.Management.Automation/engine/parser/ConstantValues.cs	Updated type check patterns in constant value visitors
src/System.Management.Automation/engine/parser/Compiler.cs	Modernized type check patterns in binary expression compilation

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