Remove the "Candy" category and fold its contents into "Appearance"

Summary:
The "Candy" category suffers from some problems:
- It does not need to exist; everything in it is purely appearance-related and could live in the existing "Appearance" category
- The name is inappropriate; "Eye Candy" would be better, but changing it to this has proven controversial in the past

Let's just remove the category and move everything in it into the "Appearance" category.

Test Plan:
Apply and compile
Open Desktop Effects KCM
See that the "Candy" category is no more and the "Appearance" category has more stuff in it

Reviewers: #kwin, #vdg, zzag, abetts

Reviewed By: #kwin, #vdg, zzag, abetts

Subscribers: abetts, zzag, kwin, kde-doc-english, GB_2

Tags: #kwin, #documentation

Differential Revision: https://phabricator.kde.org/D27658

doc/kwineffects/index.docbook

@@ -32,7 +32,7 @@ for Plasma.</para>
 
 <para>The main part of this page is a list of all available effects grouped 
 by <guilabel>Accessibility</guilabel>, <guilabel>Appearance</guilabel>, 
-<guilabel>Focus</guilabel>, <guilabel>Tools</guilabel>, <guilabel>Candy</guilabel> 
+<guilabel>Focus</guilabel>, <guilabel>Tools</guilabel>,
 and <guilabel>Window Management</guilabel>.</para>
 <para>Use the incremental search bar above the list window to find items in the list.</para>
 
@@ -79,7 +79,6 @@ functionality from KWin Core or provide interaction with other elements of the d
 39 effects + 7 internal (XRender compositor)
 Internal effects
 Appearance (Dashboard, Highlight Windows, KSreen, Screenshot, Window Geometry)
-Candy (Startup feedback)
 Window Management (Cover Switch)
 -->
 

effects/effect_builtins.cpp

@@ -221,7 +221,7 @@ EFFECT_FALLBACK
         QStringLiteral("fallapart"),
         i18ndc("kwin_effects", "Name of a KWin Effect", "Fall Apart"),
         i18ndc("kwin_effects", "Comment describing the KWin Effect", "Closed windows fall into pieces"),
-        QStringLiteral("Candy"),
+        QStringLiteral("Appearance"),
         QString(),
         QUrl(),
         false,
@@ -446,7 +446,7 @@ EFFECT_FALLBACK
         QStringLiteral("sheet"),
         i18ndc("kwin_effects", "Name of a KWin Effect", "Sheet"),
         i18ndc("kwin_effects", "Comment describing the KWin Effect", "Make modal dialogs smoothly fly in and out when they are shown or hidden"),
-        QStringLiteral("Candy"),
+        QStringLiteral("Appearance"),
         QString(),
         QUrl(),
         false,
@@ -551,7 +551,7 @@ EFFECT_FALLBACK
         QStringLiteral("startupfeedback"),
         i18ndc("kwin_effects", "Name of a KWin Effect", "Startup Feedback"),
         i18ndc("kwin_effects", "Comment describing the KWin Effect", "Helper effect for startup feedback"),
-        QStringLiteral("Candy"),
+        QStringLiteral("Appearance"),
         QString(),
         QUrl(),
         true,
@@ -626,7 +626,7 @@ EFFECT_FALLBACK
         QStringLiteral("wobblywindows"),
         i18ndc("kwin_effects", "Name of a KWin Effect", "Wobbly Windows"),
         i18ndc("kwin_effects", "Comment describing the KWin Effect", "Deform windows while they are moving"),
-        QStringLiteral("Candy"),
+        QStringLiteral("Appearance"),
         QString(),
         QUrl(QStringLiteral("https://files.kde.org/plasma/kwin/effect-videos/wobbly_windows.ogv")),
         false,

kcmkwin/common/effectsmodel.cpp

@@ -50,7 +50,6 @@ static QString translatedCategory(const QString &category)
     static const QVector<QString> knownCategories = {
         QStringLiteral("Accessibility"),
         QStringLiteral("Appearance"),
-        QStringLiteral("Candy"),
         QStringLiteral("Focus"),
         QStringLiteral("Show Desktop Animation"),
         QStringLiteral("Tools"),
@@ -62,7 +61,6 @@ static QString translatedCategory(const QString &category)
     static const QVector<QString> translatedCategories = {
         i18nc("Category of Desktop Effects, used as section header", "Accessibility"),
         i18nc("Category of Desktop Effects, used as section header", "Appearance"),
-        i18nc("Category of Desktop Effects, used as section header", "Candy"),
         i18nc("Category of Desktop Effects, used as section header", "Focus"),
         i18nc("Category of Desktop Effects, used as section header", "Show Desktop Animation"),
         i18nc("Category of Desktop Effects, used as section header", "Tools"),