Fix typos

[Marcofann]

This pull request corrects grammatical errors in type definition files (.d.ts) and a source file (formatting.ts) to improve clarity and accuracy in documentation and comments.

Summary of Changes:

1. Grammatical Fixes:

   • Replaced "an value" with "a value" in fixednumber.d.ts.
   • Updated "a expected" to "an expected" in formatting.d.ts and formatting.ts.

2. Files Modified:

   • lib.commonjs/utils/fixednumber.d.ts
   • lib.esm/providers/formatting.d.ts
   • lib.esm/utils/fixednumber.d.ts
   • src.ts/providers/formatting.ts

[ricmoo]

Merged.

Thanks! :)