Correct locale string rendering (#30522)

Since #29165, the translations are rendered as HTML in templates, so:

1. if the translation does contain `<>`, use `TrString`
2. use `{dummy}` instead of `<dummy>` as much as possible

Co-authored-by: Giteabot <teabot@gitea.io>

options/locale/locale_en-US.ini

@@ -714,7 +714,7 @@ cancel = Cancel
 language = Language
 ui = Theme
 hidden_comment_types = Hidden comment types
-hidden_comment_types_description = Comment types checked here will not be shown inside issue pages. Checking "Label" for example removes all "<user> added/removed <label>" comments.
+hidden_comment_types_description = Comment types checked here will not be shown inside issue pages. Checking "Label" for example removes all "{user} added/removed {label}" comments.
 hidden_comment_types.ref_tooltip = Comments where this issue was referenced from another issue/commit/…
 hidden_comment_types.issue_ref_tooltip = Comments where the user changes the branch/tag associated with the issue
 comment_type_group_reference = Reference
@@ -1289,7 +1289,7 @@ editor.or = or
 editor.cancel_lower = Cancel
 editor.commit_signed_changes = Commit Signed Changes
 editor.commit_changes = Commit Changes
-editor.add_tmpl = Add '<filename>'
+editor.add_tmpl = Add '{filename}'
 editor.add = Add %s
 editor.update = Update %s
 editor.delete = Delete %s
@@ -3087,14 +3087,14 @@ auths.tips = Tips
 auths.tips.oauth2.general = OAuth2 Authentication
 auths.tips.oauth2.general.tip = When registering a new OAuth2 authentication, the callback/redirect URL should be:
 auths.tip.oauth2_provider = OAuth2 Provider
-auths.tip.bitbucket = Register a new OAuth consumer on https://bitbucket.org/account/user/<your username>/oauth-consumers/new and add the permission 'Account' - 'Read'
+auths.tip.bitbucket = Register a new OAuth consumer on https://bitbucket.org/account/user/{your-username}/oauth-consumers/new and add the permission 'Account' - 'Read'
 auths.tip.nextcloud = Register a new OAuth consumer on your instance using the following menu "Settings -> Security -> OAuth 2.0 client"
 auths.tip.dropbox = Create a new application at https://www.dropbox.com/developers/apps
 auths.tip.facebook = Register a new application at https://developers.facebook.com/apps and add the product "Facebook Login"
 auths.tip.github = Register a new OAuth application on https://github.com/settings/applications/new
 auths.tip.gitlab_new = Register a new application on https://gitlab.com/-/profile/applications
 auths.tip.google_plus = Obtain OAuth2 client credentials from the Google API console at https://console.developers.google.com/
-auths.tip.openid_connect = Use the OpenID Connect Discovery URL (<server>/.well-known/openid-configuration) to specify the endpoints
+auths.tip.openid_connect = Use the OpenID Connect Discovery URL "https://{server}/.well-known/openid-configuration" to specify the endpoints
 auths.tip.twitter = Go to https://dev.twitter.com/apps, create an application and ensure that the “Allow this application to be used to Sign in with Twitter” option is enabled
 auths.tip.discord = Register a new application on https://discordapp.com/developers/applications/me
 auths.tip.gitea = Register a new OAuth2 application. Guide can be found at https://docs.gitea.com/development/oauth2-provider

templates/install.tmpl

@@ -174,7 +174,7 @@
 						<div class="inline field {{if .Err_SMTPFrom}}error{{end}}">
 							<label for="smtp_from">{{ctx.Locale.Tr "install.smtp_from"}}</label>
 							<input id="smtp_from" name="smtp_from" value="{{.smtp_from}}">
-							<span class="help">{{ctx.Locale.Tr "install.smtp_from_helper"}}</span>
+							<span class="help">{{ctx.Locale.TrString "install.smtp_from_helper"}}{{/* it contains lt/gt chars*/}}</span>
 						</div>
 						<div class="inline field {{if .Err_SMTPUser}}error{{end}}">
 							<label for="smtp_user">{{ctx.Locale.Tr "install.mailer_user"}}</label>