Tab key when indenting with spaces does not insert correct number of spaces

<!-- ⚠️⚠️ Do Not Delete This! bug_report_template ⚠️⚠️ --> <!-- Please read our Rules of Conduct: https://opensource.microsoft.com/codeofconduct/ --> <!-- Please search existing issues to avoid creating duplicates. --> <!-- Also please test using the latest insiders build to make sure your issue has not already been fixed: https://code.visualstudio.com/insiders/ --> <!-- Use Help > Report Issue to prefill these. --> - VSCode Version: 1.45.0 - OS Version: macOS Catalina 10.15.4 This is a re-filing of #80129 which was closed erroneously. This is NOT caused by an extension and reproduces when editing even a plain text document when extensions are all disabled. Related to #2798. If the insertion point is *anywhere* inside the indentation at the start of the line, and I press <kbd>Tab</kbd>, the indentation should be increased to the next full tab stop (multiple of the tab width). I'll use the period `.` character instead of spaces in indentation so that it is easier to see what I'm talking about. If I have a line of code indented by 4 spaces like this: ```python ....do_something() ``` If I place the insertion point on column 2 and press tab, I get _7_ spaces. That's really irritating, it means I have to be hyper precise placing my cursor when I want to indent a line, even when there's a very wide click target I should be able to hit anywhere. ```python .......do_something() ``` **Xcode** does this properly, it increases the indentation to 8 spaces and moves the cursor to the end of the indentation. **TextMate** behaves the same as Xcode. <!-- Launch with `code --disable-extensions` to check. --> Does this issue occur when all extensions are disabled?: Yes