Fix incorrect docstring on List.EnsureCapacity

[Smaug123]

The current docstring is false. The new capacity is computed as "twice the current capacity, and if that's still not enough, the user-specified capacity", as demonstrated in net8.0.100:

> open System;;
> let arr = ResizeArray<int> 3;;
val arr: ResizeArray<int>

> arr.Capacity;;
val it: int = 3

> arr.EnsureCapacity 9;;
val it: int = 9

> arr.Capacity;;
val it: int = 9

> arr.EnsureCapacity 11;;
val it: int = 18

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Issue Details

---

The current docstring is false. The new capacity is computed as "twice the current capacity, and if that's still not enough, the user-specified capacity", as demonstrated in net8.0.100:

> open System;;
> let arr = ResizeArray<int>();;
val arr: ResizeArray<int>

> arr.Capacity;;
val it: int = 0

> arr.EnsureCapacity 9;;
val it: int = 9

> arr.Capacity;;
val it: int = 9

Author:	Smaug123
Assignees:	-
Labels:	area-System.Collections, community-contribution
Milestone:	-

[eiriktsarpalis]

Thanks!

[jkotas]

This fix should be ported to official docs at https://github.com/dotnet/dotnet-api-docs/blob/c13606c90f809a9f04ca31db11d9701c696240f1/xml/System.Collections.Generic/List%601.xml#L1498-L1499

Also, do other collections have the same problem? E.g. https://learn.microsoft.com/en-us/dotnet/api/system.collections.generic.stack-1.ensurecapacity?view=net-7.0#definition