Add `\bigsolidus` → `⧸` abbreviation
Add `\bigsolidus` → `⧸` abbreviation

Co-authored-by: Eric Wieser <da64e90baec5d084ce3d8e05f3b022ae6d118ff5@gmail.com>
leanprover/vscode-lean,leanprover/vscode-lean,leanprover/vscode-lean