Add icon button style.

frontend/src/app/components/publication-edition/code-block-dialog/code-block-dialog.component.ts

@@ -6,6 +6,7 @@ import { MatFormFieldModule } from "@angular/material/form-field";
 import { MatIcon } from "@angular/material/icon";
 import { MatInputModule } from "@angular/material/input";
 import { MatSelectModule } from '@angular/material/select';
+import { MatTooltip } from "@angular/material/tooltip";
 
 export interface ProgramingLanguage {
     code: string;
@@ -94,6 +95,7 @@ export const PROGRAMMING_LANGUAGES: ProgramingLanguage[] = [
         MatInputModule,
         MatRippleModule,
         MatSelectModule,
+        MatTooltip,
         ReactiveFormsModule,
     ]
 })