readarray: add page (#15248)

Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>
Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/readarray.md

@@ -0,0 +1,20 @@
+# readarray
+
+> Read lines from `stdin` into an array.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-readarray>.
+
+- Interactively input lines into an array:
+
+`readarray {{array_name}}`
+
+- Read lines from a file and insert them in an array:
+
+`readarray {{array_name}} < {{path/to/file.txt}}`
+
+- Remove trailing deliminators (newline by default):
+
+`readarray -t {{array_name}} < {{path/to/file.txt}}`
+
+- Copy at most the specified number of lines:
+
+`readarray -n {{N}} {{array_name}} < {{path/to/file.txt}}`