Refactoring of src/buffered_input.jl

[Paalon]

This PR includes the following improvements:

• Use _ for a discarded value.
• Don't calculate the same value twice.
• Replace Vector{Char}(undef, 0) to Char[].
• Remove end of function returns.
• Replace string(x...) to String(x) for x::Vector{Char}. It is approximately 9 times faster and less allocations. https://discourse.julialang.org/t/for-x-vector-char-which-should-i-use-string-x-or-join-x/115469

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.05%. Comparing base (844ad27) to head (f5020fc).
Report is 5 commits behind head on master.

❗ Current head f5020fc differs from pull request most recent head c828316

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Additional details and impacted files

@@            Coverage Diff             @@
##           master     #156      +/-   ##
==========================================
+ Coverage   86.59%   87.05%   +0.46%     
==========================================
  Files          12       12              
  Lines        1626     1630       +4     
==========================================
+ Hits         1408     1419      +11     
+ Misses        218      211       -7     

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[GunnarFarneback]

• Don't calculate the same value twice.

This is often a good idea but I think it's questionable whether replacing i + 1 with i1 really makes the code clearer. (And performance changes are at best marginal.)

• Remove end of function returns.

This is a kind of opinionated style change that I wouldn't make to an existing code base.

Everything else I fully agree with.

[kescobo]

This is a kind of opinionated style change that I wouldn't make to an existing code base.

And furthermore, I actually prefer explicit returns. Otherwise, I agree, and thanks @GunnarFarneback for taking a look at these

[Paalon]

I removed these returns because this project's source code tends to not use return at the end of function, and also it's my preference in Julia. However if community wants to preserve it, I'll revert these returns.

[kescobo]

A consistent code base is more important to me than my specific preference. If that's the style elsewhere in the code, I'm fine to remove them here.

[GunnarFarneback]

tends to not use return at the end of function

Fair enough.