feat: add escaped colon support in route paths

[yuxialuozi]

Description

Add support for escaped colons (\:) in route paths to enable Google API Design Guide compliance for custom methods.

Fixes #4495

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.06%. Comparing base (3dc1cd6) to head (a3f315d).
⚠️ Report is 230 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4497      +/-   ##
==========================================
- Coverage   99.21%   99.06%   -0.15%     
==========================================
  Files          42       44       +2     
  Lines        3182     2997     -185     
==========================================
- Hits         3157     2969     -188     
- Misses         17       19       +2     
- Partials        8        9       +1     

Flag	Coverage Δ
	?
--ldflags="-checklinkname=0" -tags sonic	99.05% <100.00%> (?)
-tags go_json	98.92% <100.00%> (?)
-tags nomsgpack	98.98% <100.00%> (?)
go-1.18	?
go-1.19	?
go-1.20	?
go-1.21	?
go-1.24	99.06% <100.00%> (?)
go-1.25	98.99% <100.00%> (?)
macos-latest	98.99% <100.00%> (-0.22%)	⬇️
ubuntu-latest	99.06% <100.00%> (-0.15%)	⬇️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

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

[yuxialuozi]

I may have misunderstood Google's intention, or Google indeed means this, but it's very difficult for me to implement. So I'll close this PR for now. There have been many parameter binding errors and route matching errors. Additionally, I suggest using /v1/files/123/push instead of /v1/files/123:push.