docs: fix typo (#254)

README.md

@@ -107,7 +107,7 @@ Generates a [version 3 sourcemap](https://docs.google.com/document/d/1U1RGAehQwR
 * `file` - the filename where you plan to write the sourcemap
 * `source` - the filename of the file containing the original source
 * `includeContent` - whether to include the original content in the map's `sourcesContent` array
-* `hires` - whether the mapping should be high-resolution. Hi-res mappings map every single character, meaning (for example) your devtools will always be able to pinpoint the exact location of function calls and so on. With lo-res mappings, devtools may only be able to identify the correct line - but they're quicker to generate and less bulky. If sourcemap locations have been specified with `s.addSourceMapLocation()`, they will be used here.
+* `hires` - whether the mapping should be high-resolution. Hi-res mappings map every single character, meaning (for example) your devtools will always be able to pinpoint the exact location of function calls and so on. With lo-res mappings, devtools may only be able to identify the correct line - but they're quicker to generate and less bulky. If sourcemap locations have been specified with `s.addSourcemapLocation()`, they will be used here.
 
 The returned sourcemap has two (non-enumerable) methods attached for convenience: