Add Merge Sorted Arrays Algorithm with Type Hints and Doctests

[JainRamyak]

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
• 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 #ISSUE-NUMBER".

Additional Notes:

This PR adds the merge_sorted_arrays algorithm, which merges two sorted arrays into one sorted array using a two-pointer approach. It includes type hints and comprehensive doctests.

[algorithms-keeper]

Click here to look at the relevant links ⬇️

🔗 Relevant Links

Repository:

• Contributing guidelines
• Project Euler solution guidelines

Python:

• Formatted string literals (f-strings)
• Type hints
• doctest
• unittest
• pytest

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[algorithms-keeper]

An error occurred while parsing the file: data_structures/arrays/merge_sorted.py

Traceback (most recent call last):
  File "/opt/render/project/src/algorithms_keeper/parser/python_parser.py", line 137, in parse
    runner = LintRunner(file.path, source)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
libcst._exceptions.ParserSyntaxError: Syntax Error @ 44:19.
parser error: error at 43:18: expected one of !=, %, &, (, *, **, +, ,, -, ., /, //, :, ;, <, <<, <=, =, ==, >, >=, >>, @, NEWLINE, [, ^, and, if, in, is, not, or, |

            raise ValueError(msg)
                  ^