Remove array/object allocs during Alt+Numpad composition, improve performance

[h3xds1nz]

Description

Removes unnecessary byte[] , char[] and StringBuilder alocations during post-input processing when the char is inputted via Alt+Numpad combination. This is not somewhat impactful allocation but it will allow for more optimizations in the future.

Time spent is cut by 2/5 which is more impactful in this case.

GetCurrentOEMCPEncoding method chain call

Method	Mean [ns]	Error [ns]	StdDev [ns]	Gen0	Code Size [B]	Allocated [B]
Original	48.77 ns	0.674 ns	0.630 ns	0.0086	814 B	144 B
PR_EDIT	31.83 ns	0.292 ns	0.273 ns	0.0019	418 B	32 B

Customer Impact

Improved performance, decreased allocations.

Regression

No.

Testing

Local build, text input.

Risk

Low.

Microsoft Reviewers: Open in CodeFlow

[himgoyalmicro]

@h3xds1nz this PR is good to be merged. Can you please resolve the merge conflicts?

[h3xds1nz]

@himgoyalmicro Done :)

[himgoyalmicro]

Thank you @h3xds1nz for your consistent and valuable contributions. 😄😄

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 50 lines in your changes missing coverage. Please review.

Project coverage is 11.21741%. Comparing base (4aff730) to head (9879f39).
Report is 4 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main       #9954         +/-   ##
===================================================
- Coverage   11.28308%   11.21741%   -0.06568%     
===================================================
  Files           3353        3353                 
  Lines         668062      668051         -11     
  Branches       74980       74980                 
===================================================
- Hits           75378       74938        -440     
- Misses        591433      591867        +434     
+ Partials        1251        1246          -5     

Flag	Coverage Δ
Debug	11.21741% <0.00000%> (-0.06568%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[h3xds1nz]

@himgoyalmicro Thank you for merging :)