Layout, textual, syntactical changes documentation

Some layout, textual, syntactical changes in the documentation
- extsearch.doc better left and right ceil (so they span the total vertical part of the formula
- htmldcmds.doc, xmlcmds.doc, Doxyfile
  Correction of the positioning in the "HTML Command" / "XML Command" filed as the command was positioned properly at the top resulting in more required space for the table.
  Solution based on: https://tex.stackexchange.com/questions/376373/hyperref-inserts-vertical-space-in-tabular-cell

Author: albert-github

doc/Doxyfile

@@ -56,6 +56,8 @@ HTML_EXTRA_FILES += translator_report.txt
 ALIASES           = LaTeX="\f({\LaTeX}\f)"
 ALIASES          += TeX="\f({\TeX}\f)"
 ALIASES          += forceNewPage="\latexonly \newpage \endlatexonly"
+ALIASES          += startalign=" \latexonly\noalign{\endlatexonly"
+ALIASES          += endalign=" \latexonly}\endlatexonly"
 LATEX_BATCHMODE   = YES
 LATEX_EXTRA_STYLESHEET = manual.sty
 LATEX_EMOJI_DIRECTORY  = ../doc

doc/commands.doc

@@ -902,10 +902,8 @@ Structural indicators
   \addindex \\name
 
   This command turns a comment block into a header
-  definition of a member group. The
-  comment block should be followed by a
-  <code>///\@{ ... ///\@}</code> block containing the
-  members of the group.
+  definition of a member group. The comment block should be followed by a
+  `@{` ... `@}` block containing the members of the group.
 
   See section \ref memgroup for an example.
 
@@ -2076,7 +2074,7 @@ void setPosition(double x,double y,double z,double t)
   for an example.
 
 <hr>
-\section cmdxrefitem \\xrefitem <key> "(heading)" "(list title)" { text }
+\section cmdxrefitem \\xrefitem <key> "heading" "list title" { text }
 
  \addindex \\xrefitem
  This command is a generalization of commands such as \ref cmdtodo "\\todo"
@@ -2091,7 +2089,8 @@ void setPosition(double x,double y,double z,double t)
  is a quoted string representing the heading of the section under which
  text passed as the fourth argument is put. The third argument (list title)
  is used as the title for the related page containing all items with the
- same key. The keys \c "todo", \c "test", \c "bug" and \c "deprecated" are predefined.
+ same key. The second and third string argument cannot contain a newline.
+ The keys \c "todo", \c "test", \c "bug" and \c "deprecated" are predefined.
 
  To get an idea on how to use the \c \\xrefitem command and what its effect
  is, consider the todo list, which (for English output) can be seen an

doc/extsearch.doc

@@ -278,7 +278,7 @@ The fields have the following meaning:
 - *first*: the index of first result returned: \f$\min(n*p,\mbox{\em hits})\f$.
 - *count*: the actual number of results returned: \f$\min(n,\mbox{\em hits}-\mbox{\em first})\f$
 - *page*:  the page number of the result: \f$p\f$
-- *pages*: the total number of pages: \f$\lceil\frac{\mbox{\em hits}}{n}\rceil\f$.
+- *pages*: the total number of pages: \f$\left\lceil\frac{\mbox{\em hits}}{n}\right\rceil\f$.
 - *items*: an array containing the search data per result.
 
 Here is an example of how the element of the *items* array should look like: