Update error to reflect that integer literals can have float suffixes

For example, `1` is parsed as an integer literal, but it can be turned
into a float with the suffix `f32`. Now the error calls them "numeric
literals" and notes that you can add a float suffix since they can be
either integers or floats.

tests/ui/crashes/ice-3891.stderr

@@ -1,10 +1,10 @@
-error: invalid suffix `x` for integer literal
+error: invalid suffix `x` for number literal
   --> $DIR/ice-3891.rs:2:5
    |
 LL |     1x;
    |     ^^ invalid suffix `x`
    |
-   = help: the suffix must be one of the integral types (`u32`, `isize`, etc)
+   = help: the suffix must be one of the numeric types (`u32`, `isize`, `f32`, etc.)
 
 error: aborting due to previous error