Base: Add man page for pgrep

Base/usr/share/man/man1/pgrep.md

@@ -0,0 +1,19 @@
+## Name
+
+pgrep - look up processes based on name
+
+## Synopsis
+
+```sh
+$ pgrep [-d delimiter] [-i] [--invert-match] <process-name>
+```
+
+## Options
+
+* `-d`, `--delimiter`: Set the string used to delimit multiple pids
+* `-i`: Make matches case-insensitive
+* `-v`, `--invert-match`: Select non-matching lines
+
+## Arguments
+
+* `process-name`: Process name to search for