Suggest -Whelp when pass --print lints to rustc

Signed-off-by: xizheyin <xizheyin@smail.nju.edu.cn>

Author: xizheyin

compiler/rustc_session/src/config.rs

@@ -2082,6 +2082,12 @@ fn emit_unknown_print_request_help(early_dcx: &EarlyDiagCtxt, req: &str) -> ! {
     let mut diag = early_dcx.early_struct_fatal(format!("unknown print request: `{req}`"));
     #[allow(rustc::diagnostic_outside_of_impl)]
     diag.help(format!("valid print requests are: {prints}"));
+
+    if req == "lints" {
+        diag.help(format!("use `-Whelp` to print a list of lints"));
+    }
+
+    diag.help(format!("for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information"));
     diag.emit()
 }
 

tests/ui/invalid-compile-flags/print.stderr

@@ -1,4 +1,5 @@
 error: unknown print request: `yyyy`
   |
   = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
+  = help: for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information
 

tests/ui/rustc-print-info-issue-138612.rs

@@ -0,0 +1,2 @@
+//@ check-fail
+//@ compile-flags: /dev/null --print lints

tests/ui/rustc-print-info-issue-138612.stderr

@@ -0,0 +1,6 @@
+error: unknown print request: `lints`
+  |
+  = help: valid print requests are: `all-target-specs-json`, `calling-conventions`, `cfg`, `check-cfg`, `code-models`, `crate-name`, `deployment-target`, `file-names`, `host-tuple`, `link-args`, `native-static-libs`, `relocation-models`, `split-debuginfo`, `stack-protector-strategies`, `sysroot`, `target-cpus`, `target-features`, `target-libdir`, `target-list`, `target-spec-json`, `tls-models`
+  = help: use `-Whelp` to print a list of lints
+  = help: for more information, see the rustc book: https://doc.rust-lang.org/rustc/command-line-arguments.html#--print-print-compiler-information
+