pages/*: add backticks around I/O streams (#10436)

* as suggested in #10428
* standard input  => `stdin`
* standard output => `stdout`
* standard error  => `stderr`

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

pages/common/hashid.md

@@ -3,7 +3,7 @@
 > Python3 program that identifies data and password hashes.
 > More information: <https://github.com/psypanda/hashID>.
 
-- Identify hashes from standard input (through typing, copying and pasting, or piping the hash into the program):
+- Identify hashes from `stdin` (through typing, copying and pasting, or piping the hash into the program):
 
 `hashid`
 
@@ -23,6 +23,6 @@
 
 `hashid --mode --john {{hash}}`
 
-- Save output to a file instead of printing to standard output:
+- Save output to a file instead of printing to `stdout`:
 
 `hashid --outfile {{path/to/output.txt}} {{hash}}`