Use string type for current token and fingerprint

[anuraaga]

• string for current token avoids copying, it is always just a slice into the input
• Most logic use string operations so using a string for both reduces intermediate conversions to string

After

goos: darwin
goarch: arm64
pkg: github.com/corazawaf/libinjection-go
BenchmarkSQLiDriver
BenchmarkSQLiDriver/sqli
BenchmarkSQLiDriver/sqli-10         	   32025	     35962 ns/op	   49568 B/op	     297 allocs/op
BenchmarkSQLiDriver/folding
BenchmarkSQLiDriver/folding-10      	   12946	     93955 ns/op	   69889 B/op	    1718 allocs/op
BenchmarkSQLiDriver/tokens
BenchmarkSQLiDriver/tokens-10       	    6902	    165803 ns/op	  149562 B/op	    3689 allocs/op
PASS

Before

goos: darwin
goarch: arm64
pkg: github.com/corazawaf/libinjection-go
BenchmarkSQLiDriver
BenchmarkSQLiDriver/sqli
BenchmarkSQLiDriver/sqli-10         	   29260	     40245 ns/op	   65665 B/op	     320 allocs/op
BenchmarkSQLiDriver/folding
BenchmarkSQLiDriver/folding-10      	   12258	     98190 ns/op	   89521 B/op	    1841 allocs/op
BenchmarkSQLiDriver/tokens
BenchmarkSQLiDriver/tokens-10       	    6506	    179106 ns/op	  191738 B/op	    4136 allocs/op
PASS

[codecov-commenter]

Codecov Report

Base: 89.33% // Head: 89.28% // Decreases project coverage by -0.04% ⚠️

Coverage data is based on head (39b01fb) compared to base (05da3bd).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #10      +/-   ##
==========================================
- Coverage   89.33%   89.28%   -0.05%     
==========================================
  Files           8        8              
  Lines        1528     1521       -7     
==========================================
- Hits         1365     1358       -7     
  Misses        142      142              
  Partials       21       21              

Impacted Files	Coverage Δ
sqli.go	96.52% <100.00%> (-0.01%)	⬇️
sqli_helpers.go	95.74% <100.00%> (ø)
sqli_parse.go	99.25% <100.00%> (ø)
sqli_token.go	100.00% <100.00%> (ø)

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[jcchavezs]

Merging this as:
0. no API changes

1. changes look great
2. performance improved
3. Repo has good coverage level

If anything should change we can take care in a next PR.