Imports are not updated if multiple files are moved

Issue Type: Bug

When multiple files are moved from one folder to another, the prompt to update imports is only triggered for one file.

Steps to repro:

1. git clone https://github.com/9at8/vscode-update-import-test.git && cd vscode-update-import-test
2. Click on src/modules/a.ts in the explorer
3. Shift + click on src/modules/d.ts in the explorer
4. Drag these 4 files to src/modules/test and accept moving them
5. Only a.ts is prompted for updating imports

Expected:

1. Imports are updated for all files

cc: @mjbvz

VS Code version: Code - Insiders 1.49.0-insider (8e872f41d4ba7807e58938bbf861ca6a22d534aa, 2020-08-20T08:51:16.154Z) OS version: Linux x64 5.8.0-2-MANJARO

System Info

Item	Value
CPUs	Intel® Core™ i7-7500U CPU @ 2.70GHz (4 x 2100)
GPU Status	2d_canvas: enabled flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: disabled_off opengl: enabled_on protected_video_decode: unavailable_off rasterization: disabled_software skia_renderer: enabled_on video_decode: unavailable_off vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	15.51GB (1.54GB free)
Process Argv	–no-sandbox --crash-reporter-id 67c4af3b-3a6b-4a50-a37d-d89fa65036aa
Screen Reader	no
VM	0%
DESKTOP_SESSION	gnome
XDG_CURRENT_DESKTOP	GNOME
XDG_SESSION_DESKTOP	gnome
XDG_SESSION_TYPE	wayland

Extensions (24)

Extension	Author (truncated)	Version
jest-snippets	and	1.8.0
vscode-apollo	apo	1.16.7
markdown-emoji	bie	0.0.9
markdown-preview-github-styles	bie	0.1.6
vscode-eslint	dba	2.1.8
gitlens	eam	10.2.2
EditorConfig	Edi	0.15.1
prettier-vscode	esb	5.1.3
vscode-lisp-formatter	imj	1.1.3
vscode-docker	ms-	1.5.0
remote-ssh	ms-	0.51.0
remote-ssh-edit	ms-	0.51.0
remote-wsl	ms-	0.44.4
js-debug-nightly	ms-	2020.8.1917
vscode-js-profile-flame	ms-	0.0.7
vscode-markdown-notebook	ms-	0.0.10
vsliveshare	ms-	1.0.2666
vsliveshare-audio	ms-	0.1.85
vsliveshare-pack	ms-	0.4.0
debugger-for-chrome	msj	4.12.10
fish-vscode	sky	0.2.1
emacs-mcx	tut	0.20.2
org-mode	vsc	1.0.0
material-theme	zhu	3.8.5

(1 theme extensions excluded)

[devuxer]

This affects me so often, I wonder why so few people seem to be hitting this.

[sbmelvin]

I can rebase the PR within the next week 😃

How’s that rebase coming along?