ed: refresh/add pages (#7933)

* Update common/ed.md

* Create osx/ed.md

* Prefer `a specific`

* Fix quoting in common/ed

* Fix quoting in osx/ed

pages/osx/ed.md

@@ -0,0 +1,25 @@
+# ed
+
+> The original Unix text editor.
+> See also: `awk`, `sed`.
+> More information: <https://www.gnu.org/software/ed/manual/ed_manual.html>.
+
+- Start an interactive editor session with an empty document:
+
+`ed`
+
+- Start an interactive editor session with an empty document and a specific [p]rompt:
+
+`ed -p '> '`
+
+- Start an interactive editor session with an empty document and without diagnostics, byte counts and '!' prompt:
+
+`ed -s`
+
+- Edit a specific file (this shows the byte count of the loaded file):
+
+`ed {{path/to/file}}`
+
+- Replace a string with a specific replacement for all lines:
+
+`,s/{{regular_expression}}/{{replacement}}/g`