[obsidian.d.ts] Add information for View/FileView members

[svew]

This issue is an ask to add additional information to the FileView type in obsidian.d.ts, as well as some suggestions for what content to add.

View

contentEl

Current signature, and suggested edit:

/**
 * The HTML container for this view.
 * Rendered content should be added as a child of this element.
 * @public
 * @since 0.9.7
 */
containerEl: HTMLElement;

onOpen()

Current signature, and suggested edit:

/**
 * Called once after a new {@link View} instance is created.
 * The {@link View.contentEl} property should be contributed to at this point.
 * @public
 * @since 0.9.7
 */
protected onOpen(): Promise<void>;

FileView

file

Current signature, and suggested edit:

/**
 * The file currently loaded for this view.
 * May be null if no file has yet been loaded.
 * This property will be updated before {@link onLoadFile} is called when a new file is loaded.
 * @public
 */
file: TFile | null;

onLoadFile()

Current signature, and suggested edit:

/**
 * Called when opening a file in this view.
 * This may be called multiple times for the same {@link FileView} instance, such as when opening a new file in the same {@link WorkspaceLeaf}.
 * @param {TFile} file - The newly loaded file
 * @public
 */
onLoadFile(file: TFile): Promise<void>;