Clarify that minimal escaping is done and describe edge cases (#40)

Author: slevithan

readme.md

@@ -21,6 +21,8 @@ new RegExp(escapedString);
 
 You can also use this to escape a string that is inserted into the middle of a regex, for example, into a character class.
 
+Only the minimal amount of escaping is done, and developers are expected to insert escaped strings at safe positions in a `RegExp`. This keeps the output simple and gives you the best results in most cases. For edge case placements of escaped strings (such as immediately following `\0` or `\c`), the escaped value can change the meaning of the preceding or following token. If fully context-aware escaping is needed, consider interpolating a string using the [`regex`](https://github.com/slevithan/regex#interpolating-escaped-strings) package.
+
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