Fix tabs that crept into this file 😠

Author: Patrick Thomson

docs/core-grammar.md

@@ -3,28 +3,28 @@
 This is an EBNF grammar for the (experimental) core IR language.
 
 ```
-	expr ::= expr '.' expr
-	       | expr ' '+ expr
-	       | '{' expr (';' expr)* ';'? '}'
-	       | 'if' expr 'then' expr 'else' expr
-	       | ('lexical' | 'import' | 'load') expr
-	       | lit
-	       | 'let'? lvalue '=' expr
-	       | '(' expr ')'
+expr ::= expr '.' expr
+       | expr ' '+ expr
+       | '{' expr (';' expr)* ';'? '}'
+       | 'if' expr 'then' expr 'else' expr
+       | ('lexical' | 'import' | 'load') expr
+       | lit
+       | 'let'? lvalue '=' expr
+       | '(' expr ')'
 
-	lvalue ::= ident
-	         | parens expr
+lvalue ::= ident
+         | parens expr
 
-	lit ::= '#true'
-	      | '#false'
-	      | 'unit'
-	      | 'frame'
-	      | lambda
-	      | ident
+lit ::= '#true'
+      | '#false'
+      | 'unit'
+      | 'frame'
+      | lambda
+      | ident
 
-	lambda ::= ('λ' | '\') ident ('->' | '→') expr
+lambda ::= ('λ' | '\') ident ('->' | '→') expr
 
-	ident ::= [A-z_] ([A-z0-9_])*
-	        | '#{' [^{}]+ '}'
-	        | '"' [^"]+ '"'
-	```
+ident ::= [A-z_] ([A-z0-9_])*
+        | '#{' [^{}]+ '}'
+        | '"' [^"]+ '"'
+```