Add docs on trick for handling REPL

Closes #741

docs/make.jl

@@ -10,6 +10,7 @@ makedocs(;
         "config.md",
         "cookbook.md",
         "limitations.md",
+        "tricks.md",
         "debugging.md",
         "internals.md",
         "user_reference.md",

docs/src/index.md

@@ -130,7 +130,7 @@ Revise is fairly ambitious: if all is working, subject to a few [Limitations](@r
 - any package that you load with `import` or `using`
 - any script you load with [`includet`](@ref) (see [Configuring the revise mode](@ref) for important default restrictions on `includet`)
 - any file defining `Base` julia itself (with `Revise.track(Base)`)
-- any of Julia's standard libraries (with, e.g., `using Unicode; Revise.track(Unicode)`)
+- any of Julia's standard libraries (with, e.g., `using Unicode; Revise.track(Unicode)`). Some stdlibs may require special handling; see, for example, a trick for modifying [REPL](@ref editREPL).
 - any file defining `Core.Compiler` (with `Revise.track(Core.Compiler)`)
 
 The last one requires that you clone Julia and build it yourself from source.

docs/src/tricks.md

@@ -0,0 +1,23 @@
+# Tricks
+
+## [Editing code that defines REPL](@id editREPL)
+
+Updating the code in Julia's REPL stdlib requires some extra trickery, because modified method definitions can't be deployed until you exit any currently-running REPL functions, like those handling the prompt that you're using to interact with Julia. A workaround is to create a sub-REPL that you can shut down, and then restart a new one whenever you want to test new code:
+
+```
+using Revise
+using REPL
+Revise.track(REPL)
+
+term = REPL.Terminals.TTYTerminal("dumb", stdin, stdout, stderr)
+repl = REPL.LineEditREPL(term, true)
+Revise.retry()
+
+while true
+    @info("Launching sub-REPL, use `^D` to reload, `exit()` to quit.")
+    REPL.run_repl(repl)
+    Revise.retry()
+end
+```
+
+Many thanks to `staticfloat` for [contributing](https://github.com/timholy/Revise.jl/issues/741) this suggestion.