Expand and rename the "Letter Case" section in the Handbook Style Guide.
This expands the "Letter Case" section and renames it "Capitalization" at https://about.gitlab.com/handbook/style-guide/. It also makes some small capitalization adjustments.
This expands the "Letter Case" section and renames it "Capitalization" at https://about.gitlab.com/handbook/style-guide/. It also makes some small capitalization adjustments.