only show remote and details command and diff message where applicable
only show remote and details command and diff message where applicable

That being:
- The removal of the 'open in remote' and 'show commit details' commands for uncomitted changes.
- The removal of the diff message when there is no previous commit available (e.g. the line was never changed after comitting the file).

eamodio/vscode-gitlens,eamodio/vscode-gitlens,eamodio/vscode-gitlens