web: interface guidelines fixes
Typed-name confirm on org member remove, team member remove, team repository revoke and Promote. The team's add/remove and grant/revoke forms split so the confirm field sits only beside the removal.
Register email is type=email; autocomplete, autocapitalize and spellcheck set on email, username, one-time-code, SSH key and identifier fields. The MR close field accepts the "!" its placeholder shows and drops inputmode=numeric. refs.html accessible names contain the visible labels; the line-comment link names its line.
theme-color matches the rail; "…" in placeholders; tabular numbers in td.size; .pathbar wraps long segments at every width; .refdrop contains its scroll; .issuetitle balanced.
Closes #249