Source generator wishlist

[davhdavh]

In no particular order, a wish list to make it easier to write a source generator:

• GeneratorAttributeSyntaxContext has a member that provides a suggestion for the hintName used in AddSource - its a pita to ensure things are not duplicate named and doesn't exceed the 254 windows path limit
• Location has a AllLocationAreEqualWrapper, so that memoization doesn't care about where things are if a Location is in the pipeline
• GeneratorAttributeSyntaxContext has Location for easy error reporting
• Memoization algorithm uses IStructuralEquatable if available, its a pita to have to wrap all collections
• GeneratorAttributeSyntaxContext has Built-in helper to get all settings from attribute mapped to a settings object that matches the attribute
• GeneratorAttributeSyntaxContext has Built-in helper to check partial keyword in chain and get the declaration list for the output (ofcourse in a collection type that uses sequenceequals)
• AdditionalText has helper to find "parent" file if DependentUpon is set and/or way to group AdditionalText to the parent
• That "commandName": "DebugRoslynComponent", would run each rule TWICE and give error if it was uncached (ie, you fed up the compare)
• A well documented way to include the attribute in the nuget