Auto merge of #60700 - petrochenkov:preintern, r=nnethercote
Auto merge of #60700 - petrochenkov:preintern, r=nnethercote

syntax_pos: Optimize symbol interner pre-filling slightly

r? @nnethercote

graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust