fix(error): Give more idea why we are suggesting an arg

One challenge with this is finding something that generally works.
Making this work perfectly for one setting will make it inconsistent
with other settings and take up more binary size / compile time.

So in the end, I felt like just mirroring rustc (with a bit more
brevity) seemed like a decent experiment.  This will be evaluated by the
feedback on release.

This is a small part of clap-rs#4638

clap_builder/src/error/format.rs

@@ -429,19 +429,22 @@ fn try_help(styled: &mut StyledStr, help: Option<&str>) {
 fn did_you_mean(styled: &mut StyledStr, context: &str, valid: &ContextValue) {
     if let ContextValue::String(valid) = valid {
         styled.none(TAB);
-        styled.good("tip: ");
+        styled.good("tip: a similar ");
         styled.none(context);
-        styled.none(" '");
+        styled.none(" exists: '");
         styled.good(valid);
-        styled.none("' exists");
+        styled.none("'");
     } else if let ContextValue::Strings(valid) = valid {
         styled.none(TAB);
-        styled.good("tip: ");
-        styled.none(context);
-        if valid.len() > 1 {
-            styled.none("s");
+        if valid.len() == 1 {
+            styled.good("tip: a similar ");
+            styled.none(context);
+            styled.none(" exists: ");
+        } else {
+            styled.good("tip: some similar ");
+            styled.none(context);
+            styled.none("s exist: ");
         }
-        styled.none(" ");
         for (i, valid) in valid.iter().enumerate() {
             if i != 0 {
                 styled.none(", ");
@@ -450,11 +453,6 @@ fn did_you_mean(styled: &mut StyledStr, context: &str, valid: &ContextValue) {
             styled.good(valid);
             styled.none("'");
         }
-        if valid.len() == 1 {
-            styled.none(" exists");
-        } else {
-            styled.none(" exist");
-        }
     }
 }
 

tests/builder/opts.rs

@@ -448,7 +448,7 @@ fn did_you_mean() {
     static DYM: &str = "\
 error: unexpected argument '--optio' found
 
-  tip: argument '--option' exists
+  tip: a similar argument exists: '--option'
 
 Usage: clap-test --option <opt>... [positional] [positional2] [positional3]...
 
@@ -546,7 +546,7 @@ fn issue_1073_suboptimal_flag_suggestion() {
     static DYM_ISSUE_1073: &str = "\
 error: unexpected argument '--files-without-matches' found
 
-  tip: argument '--files-without-match' exists
+  tip: a similar argument exists: '--files-without-match'
 
 Usage: ripgrep-616 --files-without-match
 

tests/builder/possible_values.rs

@@ -181,7 +181,7 @@ fn possible_values_output() {
 error: invalid value 'slo' for '-O <option>'
   [possible values: slow, fast, \"ludicrous speed\"]
 
-  tip: value 'slow' exists
+  tip: a similar value exists: 'slow'
 
 For more information, try '--help'.
 ";
@@ -215,7 +215,7 @@ fn possible_values_alias_output() {
 error: invalid value 'slo' for '-O <option>'
   [possible values: slow, fast, \"ludicrous speed\"]
 
-  tip: value 'slow' exists
+  tip: a similar value exists: 'slow'
 
 For more information, try '--help'.
 ";
@@ -253,7 +253,7 @@ fn possible_values_hidden_output() {
 error: invalid value 'slo' for '-O <option>'
   [possible values: slow, fast, \"ludicrous speed\"]
 
-  tip: value 'slow' exists
+  tip: a similar value exists: 'slow'
 
 For more information, try '--help'.
 ";
@@ -292,7 +292,7 @@ fn escaped_possible_values_output() {
 error: invalid value 'ludicrous' for '-O <option>'
   [possible values: slow, fast, \"ludicrous speed\"]
 
-  tip: value 'ludicrous speed' exists
+  tip: a similar value exists: 'ludicrous speed'
 
 For more information, try '--help'.
 ";

tests/builder/subcommands.rs

@@ -100,7 +100,7 @@ fn subcmd_did_you_mean_output() {
     static DYM_SUBCMD: &str = "\
 error: unrecognized subcommand 'subcm'
 
-  tip: subcommand 'subcmd' exists
+  tip: a similar subcommand exists: 'subcmd'
   tip: to pass 'subcm' as a value, use 'dym -- subcm'
 
 Usage: dym [COMMAND]
@@ -120,7 +120,7 @@ fn subcmd_did_you_mean_output_ambiguous() {
     static DYM_SUBCMD_AMBIGUOUS: &str = "\
 error: unrecognized subcommand 'te'
 
-  tip: subcommands 'test', 'temp' exist
+  tip: some similar subcommands exist: 'test', 'temp'
   tip: to pass 'te' as a value, use 'dym -- te'
 
 Usage: dym [COMMAND]
@@ -517,7 +517,7 @@ For more information, try 'help'.
         static BAZ_EXPECTED: &str = "\
 error: unrecognized subcommand 'baz'
 
-  tip: subcommand 'bar' exists
+  tip: a similar subcommand exists: 'bar'
   tip: to pass 'baz' as a value, use ' -- baz'
 
 Usage: <COMMAND>