Refactor some Str2html code (#29397)

This PR touches the most interesting part of the "template refactoring".

1. Unclear variable type. Especially for "web/feed/convert.go":
sometimes it uses text, sometimes it uses HTML.
2. Assign text content to "RenderedContent" field, for example: `
project.RenderedContent = project.Description` in web/org/projects.go
3. Assign rendered content to text field, for example: `r.Note =
rendered content` in web/repo/release.go
4. (possible) Incorrectly calling `{{Str2html
.PackageDescriptor.Metadata.ReleaseNotes}}` in
package/content/nuget.tmpl, I guess the name Str2html misleads
developers to use it to "render string to html", but it only sanitizes.
if ReleaseNotes really contains HTML, then this is not a problem.

models/issues/comment.go

@@ -8,6 +8,7 @@ package issues
 import (
 	"context"
 	"fmt"
+	"html/template"
 	"strconv"
 	"unicode/utf8"
 
@@ -259,8 +260,8 @@ type Comment struct {
 	CommitID        int64
 	Line            int64 // - previous line / + proposed line
 	TreePath        string
-	Content         string `xorm:"LONGTEXT"`
-	RenderedContent string `xorm:"-"`
+	Content         string        `xorm:"LONGTEXT"`
+	RenderedContent template.HTML `xorm:"-"`
 
 	// Path represents the 4 lines of code cemented by this comment
 	Patch       string `xorm:"-"`

models/issues/issue.go

@@ -7,6 +7,7 @@ package issues
 import (
 	"context"
 	"fmt"
+	"html/template"
 	"regexp"
 	"slices"
 
@@ -105,7 +106,7 @@ type Issue struct {
 	OriginalAuthorID int64                  `xorm:"index"`
 	Title            string                 `xorm:"name"`
 	Content          string                 `xorm:"LONGTEXT"`
-	RenderedContent  string                 `xorm:"-"`
+	RenderedContent  template.HTML          `xorm:"-"`
 	Labels           []*Label               `xorm:"-"`
 	MilestoneID      int64                  `xorm:"INDEX"`
 	Milestone        *Milestone             `xorm:"-"`

models/issues/milestone.go

@@ -6,6 +6,7 @@ package issues
 import (
 	"context"
 	"fmt"
+	"html/template"
 	"strings"
 
 	"code.gitea.io/gitea/models/db"
@@ -47,8 +48,8 @@ type Milestone struct {
 	RepoID          int64                  `xorm:"INDEX"`
 	Repo            *repo_model.Repository `xorm:"-"`
 	Name            string
-	Content         string `xorm:"TEXT"`
-	RenderedContent string `xorm:"-"`
+	Content         string        `xorm:"TEXT"`
+	RenderedContent template.HTML `xorm:"-"`
 	IsClosed        bool
 	NumIssues       int
 	NumClosedIssues int

models/project/project.go

@@ -6,6 +6,7 @@ package project
 import (
 	"context"
 	"fmt"
+	"html/template"
 
 	"code.gitea.io/gitea/models/db"
 	repo_model "code.gitea.io/gitea/models/repo"
@@ -100,7 +101,7 @@ type Project struct {
 	CardType    CardType
 	Type        Type
 
-	RenderedContent string `xorm:"-"`
+	RenderedContent template.HTML `xorm:"-"`
 
 	CreatedUnix    timeutil.TimeStamp `xorm:"INDEX created"`
 	UpdatedUnix    timeutil.TimeStamp `xorm:"INDEX updated"`

models/repo/release.go

@@ -7,6 +7,7 @@ package repo
 import (
 	"context"
 	"fmt"
+	"html/template"
 	"net/url"
 	"sort"
 	"strconv"
@@ -80,7 +81,7 @@ type Release struct {
 	NumCommits       int64
 	NumCommitsBehind int64              `xorm:"-"`
 	Note             string             `xorm:"TEXT"`
-	RenderedNote     string             `xorm:"-"`
+	RenderedNote     template.HTML      `xorm:"-"`
 	IsDraft          bool               `xorm:"NOT NULL DEFAULT false"`
 	IsPrerelease     bool               `xorm:"NOT NULL DEFAULT false"`
 	IsTag            bool               `xorm:"NOT NULL DEFAULT false"` // will be true only if the record is a tag and has no related releases