on commit with no files selected add an option to use file under the cursor

### Is your feature request related to a problem? Please describe.
i often look on a diff of a specific file and then press `c` to commit it but by pressing `c` i just get a dialog "No files staged: You have not staged any files. Commit all files". sometimes i already start typing and trigger the "yes" which is kind of annoying for me.

### Describe the solution you'd like
not a change of the default behavior but an option where i can modify the behavior of this to ask if i want to commit the file "filename" under the cursor.
or a select dialog where i can choose between all, all like with `git add -u` see #1641 or only current file under the cursor (with maybe an option what is preselected)

### Describe alternatives you've considered
-

### Additional context
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Start by tracing the commit action that shows the “No files staged” dialog when no files are selected. Done means adding a configurable choice for all files, git add -u-like files, or only the file under the cursor, while preserving the current default behavior.

Written by the indexing model from the issue text.