[scss] don't autocomplete in comments

Issue Type: <b>Bug</b> I'm trying to type a scss comment. However, autocomplete is presenting useless suggestions for the content of the comment. For example, here I've typed a colon because I'm about to type a list. However, autocomplete has presented a list of junk, so when I press enter, it's going to prefill some junk instead of a newline like I wanted.  VS Code version: Code 1.67.1 (da15b6fd3ef856477bf6f4fb29ba1b7af717770d, 2022-05-06T12:37:16.526Z) OS version: Darwin x64 20.6.0 Restricted Mode: No <details> <summary>System Info</summary> |Item|Value| |---|---| |CPUs|Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz (12 x 2600)| |GPU Status|2d_canvas: enabled<br>canvas_oop_rasterization: disabled_off<br>direct_rendering_display_compositor: disabled_off_ok<br>gpu_compositing: enabled<br>metal: disabled_off<br>multiple_raster_threads: enabled_on<br>oop_rasterization: enabled<br>opengl: enabled_on<br>rasterization: enabled<br>raw_draw: disabled_off_ok<br>skia_renderer: enabled_on<br>video_decode: enabled<br>video_encode: enabled<br>webgl: enabled<br>webgl2: enabled| |Load (avg)|2, 3, 4| |Memory (System)|16.00GB (0.24GB free)| |Process Argv|--crash-reporter-id 656c6348-b102-4b6b-8ade-e7f56a3faa5f| |Screen Reader|no| |VM|0%| </details><details><summary>Extensions (10)</summary> Extension|Author (truncated)|Version ---|---|--- cform|aws|0.0.24 go|gol|0.33.0 vscode-scss|mrm|0.10.0 vscode-docker|ms-|1.22.0 vscode-kubernetes-tools|ms-|1.3.8 remote-containers|ms-|0.234.0 cpptools|ms-|1.9.8 vscode-commons|red|0.0.6 vscode-yaml|red|1.7.0 vscode-proto3|zxh|0.5.5 </details><details> <summary>A/B Experiments</summary> ``` vsliv368cf:30146710 vsreu685:30147344 python383:30185418 vspor879:30202332 vspor708:30202333 vspor363:30204092 pythonvspyl392:30443607 pythontb:30283811 pythonvspyt551cf:30345471 pythonptprofiler:30281270 vshan820:30294714 vste…