fix(Assertion): Refactor methods for setting failure and success messages

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartexpect',
-  version: '1.2.0',
+  version: '1.2.1',
   description: 'A testing library to manage expectations in code, offering both synchronous and asynchronous assertion methods.'
 }

ts/smartexpect.classes.assertion.ts

@@ -32,13 +32,13 @@ export class Assertion {
   }
 
   private failMessage: string;
-  public withFailMessage(failMessageArg: string) {
+  public setFailMessage(failMessageArg: string) {
     this.failMessage = failMessageArg;
     return this;
   }
 
   private successMessage: string;
-  public withSuccessMessage(successMessageArg: string) {
+  public setSuccessMessage(successMessageArg: string) {
     this.successMessage = successMessageArg;
     return this;
   }