Add support for sed as a programming language (#4093)

vendor/README.md

@@ -329,6 +329,7 @@ This is a list of grammars that Linguist selects to provide syntax highlighting
 - **Scheme:** [textmate/scheme.tmbundle](https://github.com/textmate/scheme.tmbundle)
 - **Scilab:** [textmate/scilab.tmbundle](https://github.com/textmate/scilab.tmbundle)
 - **SCSS:** [MarioRicalde/SCSS.tmbundle](https://github.com/MarioRicalde/SCSS.tmbundle)
+- **sed:** [Alhadis/language-sed](https://github.com/Alhadis/language-sed)
 - **ShaderLab:** [tgjones/shaders-tmLanguage](https://github.com/tgjones/shaders-tmLanguage)
 - **Shell:** [atom/language-shellscript](https://github.com/atom/language-shellscript)
 - **ShellSession:** [atom/language-shellscript](https://github.com/atom/language-shellscript)

vendor/licenses/grammar/language-sed.txt

@@ -0,0 +1,18 @@
+---
+type: grammar
+name: language-sed
+license: isc
+---
+Copyright (c) 2018, John Gardner
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.