Refactor git diff handling

[prymitive]

Stop using git blame for calculating modified lines, use git diff instead.
This allows us to drop fetching of diffs from reporter APIs.

[github-actions]

This pull request was validated by pint.

✔️ No problems found

Stats

Stat	Value
Version	v0.80.0-25-gc2cb012c
Number of rules parsed	9
Number of rules checked	9
Number of problems found	0
Number of offline checks	0
Number of online checks	0
Checks duration	0

Problems

No problems reported

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.46%. Comparing base (01e5c6c) to head (c2cb012).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1779      +/-   ##
==========================================
+ Coverage   99.44%   99.46%   +0.02%     
==========================================
  Files         113      113              
  Lines       13752    13739      -13     
==========================================
- Hits        13675    13665      -10     
+ Misses         42       40       -2     
+ Partials       35       34       -1     

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[github-actions]

Benchmark diff:

goos: linux
goarch: amd64
pkg: github.com/cloudflare/pint/cmd/pint
cpu: Intel(R) Xeon(R) Platinum 8370C CPU @ 2.80GHz
                    │   old.txt   │              new.txt               │
                    │   sec/op    │   sec/op     vs base               │
GlobFinder-4          19.17m ± 5%   18.22m ± 2%  -4.94% (p=0.029 n=10)
GitFinder-4           300.5m ± 8%   277.7m ± 1%  -7.60% (p=0.019 n=10)
CheckRules-4           9.603 ± 1%    9.615 ± 1%       ~ (p=0.853 n=10)
RuleIsIdentical-4     4.496m ± 1%   4.498m ± 0%       ~ (p=0.579 n=10)
GetChecksForEntry-4   110.8m ± 1%   110.0m ± 1%       ~ (p=0.052 n=10)
geomean               122.5m        119.2m       -2.66%

                    │    old.txt     │                new.txt                │
                    │      B/op      │     B/op      vs base                 │
GlobFinder-4          7.151Mi ± 0%     7.342Mi ± 0%  +2.67% (p=0.000 n=10)
GitFinder-4           16.10Mi ± 1%     16.38Mi ± 1%  +1.75% (p=0.000 n=10)
CheckRules-4          899.8Mi ± 0%     899.4Mi ± 0%       ~ (p=0.631 n=10)
RuleIsIdentical-4       0.000 ± 0%       0.000 ± 0%       ~ (p=1.000 n=10) ¹
GetChecksForEntry-4   56.84Mi ± 0%     56.84Mi ± 0%  -0.00% (p=0.034 n=10)
geomean                            ²                 +0.87%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

                    │    old.txt    │               new.txt                │
                    │   allocs/op   │  allocs/op   vs base                 │
GlobFinder-4          111.1k ± 0%     111.2k ± 0%  +0.07% (p=0.000 n=10)
GitFinder-4           148.8k ± 0%     146.1k ± 0%  -1.76% (p=0.000 n=10)
CheckRules-4          9.775M ± 0%     9.770M ± 0%       ~ (p=0.089 n=10)
RuleIsIdentical-4      0.000 ± 0%      0.000 ± 0%       ~ (p=1.000 n=10) ¹
GetChecksForEntry-4   927.9k ± 0%     927.9k ± 0%  -0.00% (p=0.018 n=10)
geomean                           ²                -0.35%                ²
¹ all samples are equal
² summaries must be >0 to compute geomean

pkg: github.com/cloudflare/pint/internal/parser
        │   old.txt   │            new.txt            │
        │   sec/op    │   sec/op     vs base          │
Parse-4   15.55m ± 1%   15.52m ± 1%  ~ (p=0.579 n=10)

        │   old.txt    │            new.txt             │
        │     B/op     │     B/op      vs base          │
Parse-4   6.324Mi ± 0%   6.324Mi ± 0%  ~ (p=0.912 n=10)

        │   old.txt   │             new.txt             │
        │  allocs/op  │  allocs/op   vs base            │
Parse-4   102.8k ± 0%   102.8k ± 0%  ~ (p=1.000 n=10) ¹
¹ all samples are equal

pkg: github.com/cloudflare/pint/internal/parser/source
               │   old.txt   │            new.txt            │
               │   sec/op    │   sec/op     vs base          │
LabelsSource-4   6.796m ± 1%   6.757m ± 2%  ~ (p=0.063 n=10)

               │   old.txt    │            new.txt             │
               │     B/op     │     B/op      vs base          │
LabelsSource-4   5.708Mi ± 0%   5.706Mi ± 0%  ~ (p=0.579 n=10)

               │   old.txt   │            new.txt            │
               │  allocs/op  │  allocs/op   vs base          │
LabelsSource-4   46.77k ± 0%   46.76k ± 0%  ~ (p=0.614 n=10)

pkg: github.com/cloudflare/pint/internal/promapi
                    │   old.txt    │              new.txt               │
                    │    sec/op    │   sec/op     vs base               │
QueryCacheOnlySet-4   100.65n ± 2%   98.30n ± 1%  -2.34% (p=0.002 n=10)

                    │  old.txt   │            new.txt             │
                    │    B/op    │    B/op     vs base            │
QueryCacheOnlySet-4   64.00 ± 0%   64.00 ± 0%  ~ (p=1.000 n=10) ¹
¹ all samples are equal

                    │  old.txt   │            new.txt             │
                    │ allocs/op  │ allocs/op   vs base            │
QueryCacheOnlySet-4   1.000 ± 0%   1.000 ± 0%  ~ (p=1.000 n=10) ¹
¹ all samples are equal