analyze: add syscall-filter verb

This should make it easier for users to understand what each filter
means as the list of syscalls is updated in subsequent systemd versions.

shell-completion/bash/systemd-analyze

@@ -45,6 +45,7 @@ _systemd_analyze() {
                 [DOT]='dot'
                 [LOG_LEVEL]='set-log-level'
                 [VERIFY]='verify'
+                [SECCOMP_FILTER]='syscall-filter'
         )
 
         _init_completion || return
@@ -100,6 +101,11 @@ _systemd_analyze() {
                         comps='debug info notice warning err crit alert emerg'
                 fi
 
+        elif __contains_word "$verb" ${VERBS[SECCOMP_FILTER]}; then
+                if [[ $cur = -* ]]; then
+                        comps='--help --version'
+                fi
+
         elif __contains_word "$verb" ${VERBS[VERIFY]}; then
                 if [[ $cur = -* ]]; then
                         comps='--help --version --system --user --man'