[gimp-help] Add gimp-file-overwrite help id and update Export documentation

[Jacob Boerema <jboerema src gnome org>]

commit bfccf945b9881bc4add25212c463a758cdc4cbc6
Author: Jacob Boerema <jgboerema gmail com>
Date:   Sun Oct 16 14:31:56 2022 -0400

    Add gimp-file-overwrite help id and update Export documentation
    
    (cherry picked from commit dc523403e4264e28af6bb5001eddac7589233551)

 src/menus/file/export.xml | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)
---
diff --git a/src/menus/file/export.xml b/src/menus/file/export.xml
index b9a375225..6d72c91a7 100644
--- a/src/menus/file/export.xml
+++ b/src/menus/file/export.xml
@@ -5,24 +5,25 @@
   2012-06-02 j.h: created
 -->
 <sect2 id="gimp-file-export">
-  <title>Export…</title>
+  <title>Export… and Overwrite…</title>
 
   <indexterm>
     <primary>Export</primary>
   </indexterm>
+  <indexterm>
+    <primary>Overwrite</primary>
+  </indexterm>
 
   <para>
-    This command is called <quote>Export</quote> for a native XCF file.
-    Then, it does the same thing as <command>Export As…</command>.
-    At early <application><acronym>GIMP</acronym> 2.8</application> releases,
-    this menu label was <quote>Export to</quote>.  Since the version 2.8.10,
-    <quote>Export to</quote> and <quote>Export</quote> have been renamed to
-    <quote>Export</quote> and <quote>Export As</quote> after the manner of
-    <quote>Save</quote> and <quote>Save As</quote>.
+    When the opened image is a native XCF file this command is called
+    <quote>Export</quote>. In that case, it does the same thing as
+    <command>Export As…</command>.
   </para>
+  <anchor id="gimp-file-overwrite"/>
   <para>
-    The name becomes <quote>Overwriting name.extension</quote> for an imported
-    image. So, you can export the imported image directly in its original
-    file format, without going through the export dialog.
+    When the opened image was imported, this command is called
+    <quote>Overwrite filename.extension</quote>. Using this command, you can
+    export the imported image directly in its original file format, without
+    going through the export dialog.
   </para>
 </sect2>