docs: Clarify that functions returning namespace names include underscores (not spaces)

Bug: T316092
Change-Id: I380e529590033e5d34adc37d21e8607feb4fab19

includes/Title.php

@@ -1155,7 +1155,7 @@ class Title implements LinkTarget, PageIdentity, IDBAccessObject {
 	/**
 	 * Get the namespace text
 	 *
-	 * @return string|false Namespace text
+	 * @return string|false Namespace name with underscores (not spaces), e.g. 'User_talk'
 	 */
 	public function getNsText() {
 		if ( $this->isExternal() ) {
@@ -1185,7 +1185,7 @@ class Title implements LinkTarget, PageIdentity, IDBAccessObject {
 	/**
 	 * Get the namespace text of the subject (rather than talk) page
 	 *
-	 * @return string Namespace text
+	 * @return string Namespace name with underscores (not spaces)
 	 */
 	public function getSubjectNsText() {
 		$services = MediaWikiServices::getInstance();
@@ -1196,7 +1196,7 @@ class Title implements LinkTarget, PageIdentity, IDBAccessObject {
 	/**
 	 * Get the namespace text of the talk page
 	 *
-	 * @return string Namespace text
+	 * @return string Namespace name with underscores (not spaces)
 	 */
 	public function getTalkNsText() {
 		$services = MediaWikiServices::getInstance();

includes/language/Language.php

@@ -595,9 +595,11 @@ class Language {
 	/**
 	 * Get a namespace value by key
 	 *
+	 * Namespace name uses underscores (not spaces), e.g. 'MediaWiki_talk'.
+	 *
 	 * <code>
-	 * $mw_ns = $lang->getNsText( NS_MEDIAWIKI );
-	 * echo $mw_ns; // prints 'MediaWiki'
+	 * $mw_ns = $lang->getNsText( NS_MEDIAWIKI_TALK );
+	 * echo $mw_ns; // prints 'MediaWiki_talk'
 	 * </code>
 	 *
 	 * @param int $index The array key of the namespace to return

includes/title/MediaWikiTitleCodec.php

@@ -113,7 +113,7 @@ class MediaWikiTitleCodec implements TitleFormatter, TitleParser {
 	 * @param string $text
 	 *
 	 * @throws InvalidArgumentException If the namespace is invalid
-	 * @return string Namespace name with underscores (not spaces)
+	 * @return string Namespace name with underscores (not spaces), e.g. 'User_talk'
 	 */
 	public function getNamespaceName( $namespace, $text ) {
 		if ( $this->language->needsGenderDistinction() &&

includes/title/TitleFormatter.php

@@ -97,7 +97,7 @@ interface TitleFormatter {
 	 * @param string $text
 	 *
 	 * @throws InvalidArgumentException
-	 * @return string
+	 * @return string Namespace name with underscores (not spaces), e.g. 'User_talk'
 	 */
 	public function getNamespaceName( $namespace, $text );
 }