mohuishou/scu: jwc/grade/grade.go; 12 LoC

Found a possible issue in [mohuishou/scu](https://www.github.com/mohuishou/scu) at [jwc/grade/grade.go](https://github.com/mohuishou/scu/blob/f18709083717f53b894a30eff918983f112dadd3/jwc/grade/grade.go#L62-L73)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first issue it finds, so please do not limit your consideration to the contents of the below message.

> reference to grade is reassigned at line 63

[Click here to see the code in its original context.](https://github.com/mohuishou/scu/blob/f18709083717f53b894a30eff918983f112dadd3/jwc/grade/grade.go#L62-L73)

Click here to show the 12 line(s) of Go which triggered the analyzer.

```go
for i, grade := range term.Grades {
g := &grade
g.update()
g.TermName = term.TermName
switch term.TermName {
case "尚不及格":
g.Year = -1
case "曾不及格":
g.Year = -2
}
grades[i] = *g
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: f18709083717f53b894a30eff918983f112dadd3

Read jwc/grade/grade.go at lines 62-73 from commit f18709083717f53b894a30eff918983f112dadd3, focusing on the range-loop reference and the call to update. Check the behavior against Go range-variable semantics, then leave a reaction classifying the finding as Bug, Mitigated, or Desirable Behavior.

Written by the indexing model from the issue text.