Merge #9987

9987: Fix two more “a”/“an” typos r=lnicola a=steffahn

Follow-up to #9985

you guys are merging these fast 😅 

Co-authored-by: Frank Steffahn <frank.steffahn@stu.uni-kiel.de>

Author: bors[bot]

crates/hir_ty/src/diagnostics/decl_check/case_conv.rs

@@ -43,7 +43,7 @@ pub(crate) fn to_camel_case(ident: &str) -> Option<String> {
         })
         .fold((String::new(), None), |(acc, prev): (_, Option<String>), next| {
             // separate two components with an underscore if their boundary cannot
-            // be distinguished using a uppercase/lowercase case distinction
+            // be distinguished using an uppercase/lowercase case distinction
             let join = prev
                 .and_then(|prev| {
                     let f = next.chars().next()?;

crates/hir_ty/src/diagnostics/match_check/usefulness.rs

@@ -695,7 +695,7 @@ impl SubPatSet {
                     for i in 0..*alt_count {
                         let sub_set = subpats.get(&i).unwrap_or(&SubPatSet::Empty);
                         if sub_set.is_empty() {
-                            // Found a unreachable subpattern.
+                            // Found an unreachable subpattern.
                             unreachable_pats.push(expanded[i]);
                         } else {
                             fill_subpats(sub_set, unreachable_pats, cx);