Meta: Remove stale zsh shell completions for serenity.sh

If someone wants to add these back for ladybird.sh, they'll need largely
rewritten anyway.

Meta/ShellCompletions/zsh/_serenity

@@ -1,109 +0,0 @@
-#compdef serenity serenity.sh
-
-get_top_dir() {
-    git rev-parse --show-toplevel
-}
-
-get_lagom_executables() {
-    # Make completion work with user-defined source directory.
-    LADYBIRD_SOURCE_DIR="${LADYBIRD_SOURCE_DIR:-$(get_top_dir)}"
-    # If the Lagom binary directory is missing, this creates an empty list instead of erroring.
-    # Known false positives need to be filtered manually; please add new ones.
-    find "${LADYBIRD_SOURCE_DIR}/Build/lagom" -mindepth 1 -type f -executable -not -name '*.so*' \
-        -not \( -name 'a.out' -o -name 'CMake*.bin' \) \
-        -printf '%f\n' 2>/dev/null || true
-}
-
-_serenity() {
-    local args
-    args=(
-        '1:command:->commands'
-        '2:target:->targets'
-        '3:toolchain_or_executable:->toolchains_or_executables'
-        '*:: :->args'
-    )
-
-    local commands
-    commands=(
-        'help'
-        'build'
-        'install'
-        'image'
-        'run'
-        'gdb'
-        'test'
-        'delete'
-        'recreate'
-        'rebuild'
-        'kaddr2line'
-        'addr2line'
-        'rebuild-toolchain'
-        'rebuild-world'
-        'copy-src'
-    )
-
-    local targets
-    targets=(
-        'x86_64:Target x86_64 or $SERENITY_ARCH (default)'
-        'aarch64:Target aarch64'
-        'riscv64:Target riscv64'
-        'lagom:Target host machine'
-    )
-
-    local toolchains
-    toolchains=(
-        'GNU:Toolchain gcc or $SERENITY_TOOLCHAIN (default)'
-        'Clang:Toolchain clang'
-    )
-
-    local lagom_executables
-    # Prevent splitting array on spaces with IFS; bash would have `mapfile` for this.
-    IFS=$'\n'; set -f
-    lagom_executables=($(get_lagom_executables))
-    unset IFS; set +f
-
-    _arguments -C -S "$args[@]"
-
-    local command
-    command="$line[1]"
-
-    local target
-    target="$line[2]"
-
-    local toolchain
-    toolchain="$line[3]"
-
-    case "$state" in
-        commands)
-            _describe 'command' commands
-            ;;
-        targets)
-            case "$command" in
-                install|image|copy-src|kaddr2line|rebuild-toolchain|rebuild-world)
-                    # Lagom target is not supported for these, remove from targets.
-                    targets[$targets[(i)lagom]]=()
-                    ;;
-                help)
-                    # Help command has no targets.
-                    targets=()
-                    ;;
-            esac
-            _describe 'target' targets
-            ;;
-        toolchains_or_executables)
-            if [[ "$command" != help && "$target" != lagom ]]; then
-                # Toolchain-dependent invocations.
-                _describe 'toolchain_or_executable' toolchains
-            elif [[ "$command" = run && "$target" = lagom ]]; then
-                # With `run lagom` this already is the executable.
-                _describe 'toolchain_or_executable' lagom_executables
-            fi
-            ;;
-        args)
-            ;;
-    esac
-
-    return 0
-}
-
-_serenity