fix: exclude %c from splat format specifiers

splat.js

@@ -9,7 +9,7 @@ const { SPLAT } = require('triple-beam');
  * https://github.com/nodejs/node/blob/b1c8f15c5f169e021f7c46eb7b219de95fe97603/lib/util.js#L201-L230
  * @type {RegExp}
  */
-const formatRegExp = /%[scdjifoO%]/g;
+const formatRegExp = /%[sdjifoO%]/g;
 
 /**
  * Captures the number of escaped % signs in a format string (i.e. %s strings).

test/splat.test.js

@@ -136,4 +136,23 @@ describe('splat', () => {
     );
   });
 
+
+  it('%c in message with meta | preserves %c and merges meta', assumeSplat(
+    'hello %c world', [{ robotId: 5 }], info => {
+      assume(info.message).equals('hello %c world');
+      assume(info.robotId).equals(5);
+    }
+  ));
+
+  it('%c in message without meta | preserves %c in message', assumeSplat(
+    'hello %c world', [], 'hello %c world'
+  ));
+
+  it('%c mixed with valid specifiers | only interpolates valid specifiers', assumeSplat(
+    'hello %s %c world', ['test', { robotId: 5 }], info => {
+      assume(info.message).equals('hello test %c world');
+      assume(info.robotId).equals(5);
+    }
+  ));
+
 });