perf: prevent closure creation in AttributeList

[TimothyMakkison]

Use static Func to prevent closure capture of context.

Benchmarks (Timing is inaccurate)

Saves memory for attribute heavy files aka test files.

Before

Method	Mean	Error	StdDev	Gen0	Gen1	Allocated
Default_CodeFormatter_Tests	161.1 ms	5.35 ms	15.53 ms	3000.0000	1000.0000	34.57 MB
Default_CodeFormatter_Complex	323.3 ms	9.19 ms	24.86 ms	5000.0000	2000.0000	53 MB

After

Method	Mean	Error	StdDev	Median	Gen0	Gen1	Allocated
Default_CodeFormatter_Tests	134.6 ms	2.68 ms	7.06 ms	131.8 ms	3000.0000	1000.0000	34.4 MB
Default_CodeFormatter_Complex	283.3 ms	7.92 ms	22.97 ms	273.1 ms	5000.0000	2000.0000	53.01 MB