pages*: improve list placeholders and wording of descriptions (#12111)

* pages*: improve wording and list placeholders

* clamav: fix verb tenses

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>

* buzzphrase: use k instead of n for number of phrases

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>

* adguardhome: use non-default instead of different

* adguardhome: use configuration instead of config

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

* goimports, module: fix list placeholders

Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>

* pages*: leave stems and extensions in the same placeholders

* pages*: fix list placeholders

* pages*: fix list placeholders

* pages*: apply suggestions from code review

Co-authored-by: Lena <126529524+acuteenvy@users.noreply.github.com>

* qpdf: enclose n with backticks

Co-authored-by: Lena <126529524+acuteenvy@users.noreply.github.com>

---------

Co-authored-by: Juri Dispan <juri.dispan@posteo.net>
Co-authored-by: K.B.Dharun Krishna <kbdharunkrishna@gmail.com>
Co-authored-by: Lena <126529524+acuteenvy@users.noreply.github.com>

pages/common/xsv.md

@@ -17,7 +17,7 @@
 
 - Select a few columns:
 
-`xsv select {{column_a,column_b}} {{path/to/file.csv}}`
+`xsv select {{column1,column2}} {{path/to/file.csv}}`
 
 - Show 10 random entries:
 
@@ -25,4 +25,4 @@
 
 - Join a column from one file to another:
 
-`xsv join --no-case {{column_a}} {{path/to/file/a.csv}} {{column_b}} {{path/to/file/b.csv}} | xsv table`
+`xsv join --no-case {{column1}} {{path/to/file1.csv}} {{column2}} {{path/to/file2.csv}} | xsv table`