Bump the docs versions

doc/kate/index.docbook

@@ -43,8 +43,8 @@
 </copyright>
 <legalnotice>&FDLNotice;</legalnotice>
 
-<date>2021-03-06</date>
-<releaseinfo>Applications 21.04</releaseinfo>
+<date>2021-09-02</date>
+<releaseinfo>Applications 21.12</releaseinfo>
 
 <abstract>
 <para>&kate; is a programmer's text editor by &kde;.</para>

doc/katepart/index.docbook

@@ -52,8 +52,8 @@
 </copyright>
 <legalnotice>&FDLNotice;</legalnotice>
 
-<date>2020-10-10</date>
-<releaseinfo>&frameworks; 5.75</releaseinfo>
+<date>2021-09-02</date>
+<releaseinfo>&frameworks; 5.85</releaseinfo>
 
 <abstract>
 <para>&katepart; is a fully featured editor component by &kde;.</para>

doc/kwrite/index.docbook

@@ -26,8 +26,8 @@
 </copyright>
 <legalnotice>&FDLNotice;</legalnotice>
 
-<date>2018-05-19</date>
-<releaseinfo>Applications 18.08</releaseinfo>
+<date>2021-09-02</date>
+<releaseinfo>KDE Gear 21.12</releaseinfo>
 
 <abstract>
 <para>&kwrite; is a text editor by &kde; allowing you to edit one file at the time per window.</para>