Share the load-path lookup, polyvariant label printing and ident tables
Why
The same logic was kept in several copies that had to change together. Misc.find_map_in_path_uncap is now the one "name as written, then uncapitalized" lookup, used by Misc.find_in_path_uncap, Config_util and Bs_cmi_load (#8925 had changed all three). Editor completion prints polyvariant labels with Res_printer.print_poly_var_ident instead of a copy of the printer's classifier, which had drifted. Lam_check and Lam_dce use Hash_ident, which Hash_set_ident duplicated since #8787.
modifiedFormat completion label of a polymorphic variant
type t = [#644 | #""]let f = (e: t) => ignore(e)// f()// ^com
text
Before
After
#"644"##644#""