Clarify documentation for --replace.

Also add a minor clarification for --type-add.

Fixes #147

doc/rg.1.md

@@ -61,10 +61,6 @@ the raw speed of grep.
 : Do not print anything to stdout. If a match is found in a file, stop
   searching that file.
 
--r, --replace *ARG*
-: Replace every match with the string given. Capture group indices (e.g., $5)
-  and names (e.g., $foo) are supported.
-
 -t, --type *TYPE* ...
 : Only search files matching TYPE. Multiple type flags may be provided. Use the
   --type-list flag to list all available types.
@@ -168,6 +164,13 @@ the raw speed of grep.
 -p, --pretty
 : Alias for --color=always --heading -n.
 
+-r, --replace *ARG*
+: Replace every match with the string given when printing search results.
+  Neither this flag nor any other flag will modify your files.
+
+    Capture group indices (e.g., $5) and names (e.g., $foo) are supported
+    in the replacement string.
+
 -s, --case-sensitive
 : Search case sensitively. This overrides --ignore-case and --smart-case.
 
@@ -197,9 +200,10 @@ the raw speed of grep.
 : Add a new glob for a particular file type. Only one glob can be added
   at a time. Multiple --type-add flags can be provided. Unless --type-clear
   is used, globs are added to any existing globs inside of ripgrep. Note that
-  this must be passed to every invocation of rg.
+  this must be passed to every invocation of rg. Type settings are NOT
+  persisted.
 
-  Example: `--type-add html:*.html`
+      Example: `rg --type-add 'foo:*.foo' -tfoo PATTERN`
 
 --type-clear *TYPE* ...
 : Clear the file type globs previously defined for TYPE. This only clears