Update unit tests to match more limited hint about escaping.

src/test/ui/conditional-compilation/cfg-arg-invalid-2.rs

@@ -1,3 +1,3 @@
 // compile-flags: --cfg a{b}
-// error-pattern: invalid `--cfg` argument: `a{b}` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+// error-pattern: invalid `--cfg` argument: `a{b}` (expected `key` or `key="value"`)
 fn main() {}

src/test/ui/conditional-compilation/cfg-arg-invalid-2.stderr

@@ -1,2 +1,2 @@
-error: invalid `--cfg` argument: `a{b}` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+error: invalid `--cfg` argument: `a{b}` (expected `key` or `key="value"`)
 

src/test/ui/conditional-compilation/cfg-arg-invalid-4.rs

@@ -1,3 +1,3 @@
 // compile-flags: --cfg a(b)
-// error-pattern: invalid `--cfg` argument: `a(b)` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+// error-pattern: invalid `--cfg` argument: `a(b)` (expected `key` or `key="value"`)
 fn main() {}

src/test/ui/conditional-compilation/cfg-arg-invalid-4.stderr

@@ -1,2 +1,2 @@
-error: invalid `--cfg` argument: `a(b)` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+error: invalid `--cfg` argument: `a(b)` (expected `key` or `key="value"`)
 

src/test/ui/conditional-compilation/cfg-arg-invalid-6.rs

@@ -1,3 +1,3 @@
 // compile-flags: --cfg a{
-// error-pattern: invalid `--cfg` argument: `a{` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+// error-pattern: invalid `--cfg` argument: `a{` (expected `key` or `key="value"`)
 fn main() {}

src/test/ui/conditional-compilation/cfg-arg-invalid-6.stderr

@@ -1,2 +1,2 @@
-error: invalid `--cfg` argument: `a{` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+error: invalid `--cfg` argument: `a{` (expected `key` or `key="value"`)
 

src/test/ui/conditional-compilation/cfg-arg-invalid-8.rs

@@ -1,3 +1,3 @@
 // compile-flags: --cfg )
-// error-pattern: invalid `--cfg` argument: `)` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+// error-pattern: invalid `--cfg` argument: `)` (expected `key` or `key="value"`)
 fn main() {}

src/test/ui/conditional-compilation/cfg-arg-invalid-8.stderr

@@ -1,2 +1,2 @@
-error: invalid `--cfg` argument: `)` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+error: invalid `--cfg` argument: `)` (expected `key` or `key="value"`)
 

src/test/ui/conditional-compilation/cfg-arg-invalid-9.rs

@@ -1,3 +1,4 @@
+// Test for missing quotes around value, issue #66450.
 // compile-flags: --cfg key=value
 // error-pattern: invalid `--cfg` argument: `key=value` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
 fn main() {}

src/test/ui/conditional-compilation/cfg-empty-codemap.rs

@@ -2,7 +2,7 @@
 
 // compile-flags: --cfg ""
 
-// error-pattern: invalid `--cfg` argument: `""` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+// error-pattern: invalid `--cfg` argument: `""` (expected `key` or `key="value"`)
 
 pub fn main() {
 }

src/test/ui/conditional-compilation/cfg-empty-codemap.stderr

@@ -1,2 +1,2 @@
-error: invalid `--cfg` argument: `""` (expected `key` or `key="value"`, ensure escaping is appropriate for your shell, try 'key="value"' or key=\"value\")
+error: invalid `--cfg` argument: `""` (expected `key` or `key="value"`)