Fixed the algorithm in missing_numbers code

[grpathak22]

Describe your change:

changed n to last number and improved time complexity.
Considered that list is not always starting from 0

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes missing_number algorithm dosen't work as intended (bit_manipulation/missing_number.py) #10357".

[tianyizheng02]

Your changes to missing_number.py entirely changes the algorithm. The whole purpose of the problem is to use bit manipulation to find the missing number—without simply searching for the number. Furthermore, your solution breaks if the list is not in order. Ultimately it doesn't solve the issue you link.

[grpathak22]

Apologies for the wrong solution
I will try it using bit manipulation
Thank you for informing me!