This change enables user to specify the tag for the wrapping HTML element
generated from ValidationSummary() and ValidationMessage[For]().
Clean up HtmlHelperValidationExtensions.
- no more `IHtmlHelper<object>` in `DefaultDisplayTemplates` and also no
need for `ViewDataDictionary<object>` in a few places
- mostly removals from `IHtmlHelper<TModel>` but did cleanup comments and
add `[NotNull]` for `DisplayFor()`, `DisplayNameFor()`,
`DisplayNameForInnerType()`, and `LabelFor()`
- also add `[NotNull]` for `this` and `Expression` parameters in some
extension methods
- correct file and class names for some HH extensions
- three class names were correct but didn't match containing file
- three class and file names matched but didn't start with HtmlHelper
- clean up trailing whitespace and long lines in changed Extensions.cs files
- `HtmlHelperPartialAsyncExtensions`, `HtmlHelperRenderPartialAsyncExtensions`
and `HtmlHelperValidationExtensions` lacked some `[NotNull]` attributes
- merge extension files by concept
- Display / DisplayFor / DisplayForModel methods all into `HtmlHelperDisplayExtensions`
- Partial / RenderPartial methods all into `HtmlHelperPartialExtensions`
- use `IHtmlHelper<TModel>` everywhere
Tian Pan
Andrew Peters
sornaks
dougbu