I have no idea why NV Access decided to use lowercase characters in input gesture documentation when no one else in the world does, but they did. I have already suggested to them that the standard of using uppercase characters for single letters be adopted, and am suggesting it here.
While the following is mostly of concern to the sighted, there are enough sighted instructors that it matters. When the shortcut NVDA + Shift + L is written with a lowercase L, that letter is visually indistinguishable from an uppercase I in a very great many fonts, including the one used by GitHub by default. Using single uppercase letters where single letters are part of an input gesture/keyboard shortcut removes all ambiguity about which letter is being designated. It also follows the Microsoft conventions, which are the de facto world standard for keyboard shortcut notation.