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/opusenc.md

@@ -5,16 +5,16 @@
 
 - Convert WAV to Opus using default options:
 
-`opusenc {{path/to/input.wav}} {{path/to/output}}.opus`
+`opusenc {{path/to/input.wav}} {{path/to/output.opus}}`
 
 - Convert stereo audio at the highest quality level:
 
-`opusenc --bitrate {{512}} {{path/to/input.wav}} {{path/to/output}}.opus`
+`opusenc --bitrate {{512}} {{path/to/input.wav}} {{path/to/output.opus}}`
 
 - Convert 5.1 surround sound audio at the highest quality level:
 
-`opusenc --bitrate {{1536}} {{path/to/input.flac}} {{path/to/output}}.opus`
+`opusenc --bitrate {{1536}} {{path/to/input.flac}} {{path/to/output.opus}}`
 
 - Convert speech audio at the lowest quality level:
 
-`opusenc {{path/to/input.wav}} --downmix-mono --bitrate {{6}} {{path/to/out}}.opus`
+`opusenc {{path/to/input.wav}} --downmix-mono --bitrate {{6}} {{path/to/out.opus}}`