minor symfony#60732 [DependencyInjection] Improve docblock on compile() (Crell)

This PR was submitted for the 7.4 branch but it was merged into the 6.4 branch instead.

Discussion
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[DependencyInjection] Improve docblock on compile()

| Q             | A
| ------------- | ---
| Branch?       | 7.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

This is just a documentation fix to make the `$resolveEnvPlaceholders` parameter more self-explanatory.  Its current form confused me greatly and I had it set wrong because I was confused.

Commits
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d890828 Improve docblock on compile()

Author: nicolas-grekas

src/Symfony/Component/DependencyInjection/ContainerBuilder.php

@@ -742,10 +742,11 @@ public function deprecateParameter(string $name, string $package, string $versio
      *  * The parameter bag is frozen;
      *  * Extension loading is disabled.
      *
-     * @param bool $resolveEnvPlaceholders Whether %env()% parameters should be resolved using the current
-     *                                     env vars or be replaced by uniquely identifiable placeholders.
-     *                                     Set to "true" when you want to use the current ContainerBuilder
-     *                                     directly, keep to "false" when the container is dumped instead.
+     * @param bool $resolveEnvPlaceholders Whether %env()% parameters should be resolved at build time using
+     *                                     the current env var values (true), or be resolved at runtime based
+     *                                     on the environment (false). In general, this should be set to "true"
+     *                                     when you want to use the current ContainerBuilder directly, and to
+     *                                     "false" when the container is dumped instead.
      *
      * @return void
      */