[Bug preprocessor/93109] New: #undefine suggests #define but not #undef

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93109

            Bug ID: 93109
           Summary: #undefine suggests #define but not #undef
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: diagnostic
          Severity: enhancement
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

t.c:24:2: error: invalid preprocessing directive #undefine; did you mean
#define?
   24 | #undefine shift
      |  ^~~~~~~~
      |  define


I was not thinking when I was writing code for a second but the preprocessor
definitely could do better at the suggestion.