text/template: fix doc spacing

Change-Id: I4550ce3135b3cd675010a3701618e9350f282453
GitHub-Last-Rev: d2e52f1496
GitHub-Pull-Request: golang/go#68519
Reviewed-on: https://go-review.googlesource.com/c/go/+/599535
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Rob Pike <r@golang.org>

src/text/template/doc.go

@@ -162,37 +162,55 @@ An argument is a simple value, denoted by one of the following.
 	  the host machine's ints are 32 or 64 bits.
 	- The keyword nil, representing an untyped Go nil.
 	- The character '.' (period):
+
 		.
+
 	  The result is the value of dot.
 	- A variable name, which is a (possibly empty) alphanumeric string
 	  preceded by a dollar sign, such as
+
 		$piOver2
+
 	  or
+
 		$
+
 	  The result is the value of the variable.
 	  Variables are described below.
 	- The name of a field of the data, which must be a struct, preceded
 	  by a period, such as
+
 		.Field
+
 	  The result is the value of the field. Field invocations may be
 	  chained:
+
 	    .Field1.Field2
+
 	  Fields can also be evaluated on variables, including chaining:
+
 	    $x.Field1.Field2
 	- The name of a key of the data, which must be a map, preceded
 	  by a period, such as
+
 		.Key
+
 	  The result is the map element value indexed by the key.
 	  Key invocations may be chained and combined with fields to any
 	  depth:
+
 	    .Field1.Key1.Field2.Key2
+
 	  Although the key must be an alphanumeric identifier, unlike with
 	  field names they do not need to start with an upper case letter.
 	  Keys can also be evaluated on variables, including chaining:
+
 	    $x.key1.key2
 	- The name of a niladic method of the data, preceded by a period,
 	  such as
+
 		.Method
+
 	  The result is the value of invoking the method with dot as the
 	  receiver, dot.Method(). Such a method must have one return value (of
 	  any type) or two return values, the second of which is an error.
@@ -200,16 +218,22 @@ An argument is a simple value, denoted by one of the following.
 	  and an error is returned to the caller as the value of Execute.
 	  Method invocations may be chained and combined with fields and keys
 	  to any depth:
+
 	    .Field1.Key1.Method1.Field2.Key2.Method2
+
 	  Methods can also be evaluated on variables, including chaining:
+
 	    $x.Method1.Field
 	- The name of a niladic function, such as
+
 		fun
+
 	  The result is the value of invoking the function, fun(). The return
 	  types and values behave as in methods. Functions and function
 	  names are described below.
 	- A parenthesized instance of one the above, for grouping. The result
 	  may be accessed by a field or map key invocation.
+
 		print (.F1 arg1) (.F2 arg2)
 		(.StructValuedMethod "arg").Field