sh-leading-keywords

sh-leading-keywords is a variable defined in `sh-script.el'.
Its value is

((bash sh-append sh "time")
 (csh "else")
 (es "true" "unwind-protect" "whatis")
 (rc "else")
 (sh "!" "do" "elif" "else" "if" "then" "trap" "type" "until" "while"))

Documentation:
List of keywords that may be immediately followed by a builtin or keyword.
Given some confusion between keywords and builtins depending on shell and
system, the distinction here has been based on whether they influence the
flow of control or syntax. See `sh-feature'.

You can customize this variable.