fix(compiler): Enable custom tasks to be called up in watch mode

src/compiler/output-targets/output-custom.ts

@@ -4,14 +4,15 @@ import type * as d from '../../declarations';
 import { generateDocData } from '../docs/generate-doc-data';
 
 export const outputCustom = async (config: d.ValidatedConfig, compilerCtx: d.CompilerCtx, buildCtx: d.BuildCtx) => {
-  const task = config.devMode ? 'run' : 'build';
-  const docsData = await generateDocData(config, compilerCtx, buildCtx);
+  const task = config.watch ? 'always' : 'onBuildOnly';
   const customOutputTargets = config.outputTargets
     .filter(isOutputTargetCustom)
-    .filter((o) => (o.task === undefined ? true : o.task === task));
+    .filter((o) => (o.taskShouldRun === undefined ? true : o.taskShouldRun === task));
+
   if (customOutputTargets.length === 0) {
     return;
   }
+  const docsData = await generateDocData(config, compilerCtx, buildCtx);
 
   await Promise.all(
     customOutputTargets.map(async (o) => {

src/declarations/stencil-public-compiler.ts

@@ -2241,12 +2241,14 @@ export interface OutputTargetCustom extends OutputTargetBase {
   type: 'custom';
   name: string;
   /**
-   * Indicate in wich mode the output target has to be executed.
-   * By default if nothing is specified it run for both.
-   * - `"run"`: Executed in dev mode on every change in your code
-   * - `"build"`: Executed only on build
+   * Indicate when the output target should be executed.
+   * 
+   * - `"onBuildOnly"`: Executed only when `stencil build` is called without `--watch`.
+   * - `"always"`: Executed on every build, including in `watch` mode.
+   *
+   * Defaults to "always".
    */
-  task?: 'run' | 'build';
+  taskShouldRun?: 'onBuildOnly' | 'always';
   validate?: (config: Config, diagnostics: Diagnostic[]) => void;
   generator: (config: Config, compilerCtx: CompilerCtx, buildCtx: BuildCtx, docs: JsonDocs) => Promise<void>;
   copy?: CopyTask[];