docs: Edit rustc_middle::ty::query::on_disk_cache

Expand abbreviations for "incremental compliation".

Also added the word "to" to the description of CacheEncoder.

compiler/rustc_middle/src/ty/query/on_disk_cache.rs

@@ -648,7 +648,7 @@ pub(crate) fn def_path_hash_to_def_id(
 
 //- DECODING -------------------------------------------------------------------
 
-/// A decoder that can read from the incr. comp. cache. It is similar to the one
+/// A decoder that can read from the incremental compilation cache. It is similar to the one
 /// we use for crate metadata decoding in that it can rebase spans and eventually
 /// will also handle things that contain `Ty` instances.
 crate struct CacheDecoder<'a, 'tcx> {
@@ -936,7 +936,7 @@ fn decode(d: &mut CacheDecoder<'a, 'tcx>) -> Result<Self, String> {
 
 //- ENCODING -------------------------------------------------------------------
 
-/// An encoder that can write the incr. comp. cache.
+/// An encoder that can write to the incremental compilation cache.
 struct CacheEncoder<'a, 'tcx, E: OpaqueEncoder> {
     tcx: TyCtxt<'tcx>,
     encoder: &'a mut E,