Remove error line numbers and fix capitalization.

Co-authored-by: nora <[email protected]>

Author: LFS6502

compiler/rustc_parse/src/lexer/unescape_error_reporting.rs

@@ -169,7 +169,7 @@ pub(crate) fn emit_unescape_error(
                 );
 
                 diag.help(format!(
-                    "{ec} is not an ascii quote, but may look like one in some fonts; \
+                    "{ec} is not an ASCII quote, but may look like one in some fonts; \
                      consider writing it in its escaped form for clarity."
                 ));
             } else {

tests/ui/unicode-quote.rs

@@ -2,7 +2,7 @@
 // <https://github.com/rust-lang/rust/issues/128858>
 fn main() {
     dbg!("\″"); //U+2033
-    //~^ERROR 4:12: 4:13: unknown character escape: `\u{2033}`
+    //~^ERROR unknown character escape: `\u{2033}`
     dbg!("\ʺ"); //U+02BA
     //~^ERROR 6:12: 6:13: unknown character escape: `\u{2ba}`
     dbg!("\˝"); //U+02DD