Add snippets for argument parsing and fix `case` snippet#937

EmilyGraceSeville7cf wants to merge 6 commits intobash-lsp:mainbash-lsp/bash-language-server:mainfrom

EmilyGraceSeville7cf:feature/snippets-for-argument-parsingEmilyGraceSeville7cf/bash-language-server:feature/snippets-for-argument-parsingCopy head branch name to clipboard