adding none in the suggested completions list

[polatengin]

Closes #14987

Adding none option to the code completion list for using keyword in .bicepparam files

Current behavior;

Expected behavior;

Microsoft Reviewers: Open in CodeFlow

[github-actions]

Test this change out locally with the following install scripts (Action run 10760253713)

VSCode

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-vsix.sh) --run-id 10760253713

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-vsix.ps1) } -RunId 10760253713"

Azure CLI

• Mac/Linux

  bash <(curl -Ls https://aka.ms/bicep/nightly-cli.sh) --run-id 10760253713

• Windows

  iex "& { $(irm https://aka.ms/bicep/nightly-cli.ps1) } -RunId 10760253713"

[github-actions]

Dotnet Test Results

    71 files   -     37      71 suites   - 37   25m 13s ⏱️ - 9m 29s
11 046 tests  -     19  11 046 ✅  -     19  0 💤 ±0  0 ❌ ±0 
25 868 runs   - 12 927  25 868 ✅  - 12 927  0 💤 ±0  0 ❌ ±0 

Results for commit 1a8d1f4. ± Comparison against base commit 3e4958e.

♻️ This comment has been updated with latest results.