Doc: Drop obsolete Doxygen tags

doc/doxygen/Doxyfile.in

@@ -1363,15 +1363,6 @@ HTML_COLORSTYLE_SAT    = 100
 
 HTML_COLORSTYLE_GAMMA  = 80
 
-# If the HTML_TIMESTAMP tag is set to YES then the footer of each generated HTML
-# page will contain the date and time when the page was generated. Setting this
-# to YES can help to show when doxygen was last run and thus if the
-# documentation is up to date.
-# The default value is: NO.
-# This tag requires that the tag GENERATE_HTML is set to YES.
-
-HTML_TIMESTAMP         = NO
-
 # If the HTML_DYNAMIC_MENUS tag is set to YES then the generated HTML
 # documentation will contain a main index with vertical navigation menus that
 # are dynamically created via JavaScript. If disabled, the navigation index will
@@ -2032,14 +2023,6 @@ LATEX_HIDE_INDICES     = NO
 
 LATEX_BIB_STYLE        = plain
 
-# If the LATEX_TIMESTAMP tag is set to YES then the footer of each generated
-# page will contain the date and time when the page was generated. Setting this
-# to NO can help when comparing the output of multiple runs.
-# The default value is: NO.
-# This tag requires that the tag GENERATE_LATEX is set to YES.
-
-LATEX_TIMESTAMP        = NO
-
 # The LATEX_EMOJI_DIRECTORY tag is used to specify the (relative or absolute)
 # path from which the emoji images will be read. If a relative path is entered,
 # it will be relative to the LATEX_OUTPUT directory. If left blank the